U.S. patent application number 11/409771 was filed with the patent office on 2007-10-25 for method for test of electronic component.
Invention is credited to Gregory E. Thoman.
Application Number | 20070250285 11/409771 |
Document ID | / |
Family ID | 38562218 |
Filed Date | 2007-10-25 |
United States Patent
Application |
20070250285 |
Kind Code |
A1 |
Thoman; Gregory E. |
October 25, 2007 |
METHOD FOR TEST OF ELECTRONIC COMPONENT
Abstract
A method for testing an electronic component. The method
includes connecting the electronic component to a test machine;
specifying search range limits, low-to-high transition edge and
high-to-low transition edge found criterion, and number of outcomes
in a trial including multiple tests specified as proof of
low-to-high transition or as high-to-low transition; computing
values for initial trial parameters; if low-to-high transition edge
not found: executing a low-to-high trial and adjusting trial
parameter values based on results of step executing low-to-high
trial; if high-to-low transition edge not found: executing
high-to-low trial; and if either low-to-high or high-to-low
transition edge not found: adjusting trial parameter values based
on results of step executing high-to-low trial and repeating above
steps beginning with the step having the condition if low-to-high
transition edge has not been found.
Inventors: |
Thoman; Gregory E.;
(Loveland, CO) |
Correspondence
Address: |
VERIGY
4700 INNOVATION WAY, BLDG D1
FORT COLLINS
CO
80528
US
|
Family ID: |
38562218 |
Appl. No.: |
11/409771 |
Filed: |
April 24, 2006 |
Current U.S.
Class: |
702/119 ;
702/108; 702/117; 702/118; 702/123 |
Current CPC
Class: |
G01R 31/31924 20130101;
G01R 31/31932 20130101 |
Class at
Publication: |
702/119 ;
702/108; 702/117; 702/118; 702/123 |
International
Class: |
G06F 19/00 20060101
G06F019/00 |
Claims
1. A method for testing an electronic component, comprising:
specifying search range limits, low-to-high transition edge and
high-to-low transition edge found criterion, and number of
comparison outcomes in a trial comprising multiple tests specified
as proof of a low-to-high transition edge or as proof of a
high-to-low transition edge; computing initial values for trial
parameters using the search range limits, wherein the trial
parameters comprise: low-to-high band limits for a low-to-high
trial and a low-to-high trial value, high-to-low band limits for a
high-to-low trial and a high-to-low trial value, and number of high
indicating comparison outcomes from an assumed previous trial;
specifying the low-to-high transition edge and the high-to-low
transition edge as not found; if low-to-high transition edge not
found: executing the low-to-high trial on the electronic component
resulting in various low and high indicating comparison outcomes
and adjusting part of the trial parameter values based on results
of executing the low-to-high trial; if high-to-low transition edge
not found: executing the high-to-low trial on the electronic
component resulting in various low and high indicating comparison
outcomes and adjusting another part of the trial parameter values
based on results of executing the high-to-low trial; if the results
of the low-to-high trial meet the low-to-high transition edge found
criterion: specifying the low-to-high transition edge as found; if
the results of the high-to-low trial meet the high-to-low
transition edge found criterion: specifying the high-to-low
transition edge as found; if either low-to-high or high-to-low
transition edge not found: adjusting still another part of the
trial parameter values based on results of the above executed
trials and repeating the above beginning with the condition if
low-to-high transition edge not found; and storing the final trial
parameter values.
2. The method as recited in claim 1, further comprising: prior to
executing the low-to-high trial, ensuring that the electronic
component is in its low state; and prior to executing the
high-to-low trial, ensuring that the electronic component is in its
high state.
3. The method as recited in claim 1, wherein the low-to-high
transition edge found criterion and the high-to-low transition edge
found criterion depend upon a value specified for a resolution
limit of the search.
4. The method as recited in claim 3, further comprising: if the
absolute difference between upper and lower low-to-high band limits
for the low-to-high trial is less than the resolution limit of the
search, marking the low-to-high transition edge as found; and if
the absolute difference between upper and lower high-to-low band
limits for the high-to-low trial is less than the resolution limit
of the search, marking the high-to-low transition edge as
found.
5. The method as recited in claim 1, further comprising: computing
the low-to-high trial value based on the upper and lower
low-to-high band limits; and computing the high-to-low trial value
based on the upper and lower high-to-low band limits.
6. The method as recited in claim 5, wherein if either the upper
low-to-high band limit does not equal the upper high-to-low band
limit or if the lower low-to-high band limit does not equal the
lower high-to-low band limit, the computed low-to-high trial value
is equal to one-half the sum of the upper low-to-high band limit
and the lower low-to-high band limit and the computed high-to-low
trial value is equal to one-half the sum of the upper high-to-low
band limit and the lower high-to-low band limit.
7. The method as recited in claim 5, wherein if the upper
low-to-high band limit equals the upper high-to-low band limit and
if the lower low-to-high band limit equals the lower high-to-low
band limit, the computed low-to-high trial value is equal to the
sum of the lower low-to-high band limit and one-third the quantity
of the lower low-to-high band limit subtracted from the upper
low-to-high band limit and the computed high-to-low trial value is
equal to the sum of the lower high-to-low band limit and two-thirds
the quantity of the lower high-to-low band limit subtracted from
the upper high-to-low band limit.
8. A computer readable memory device having stored thereon computer
program instructions executable by the computer to perform a method
for testing an electronic component, the instructions comprising:
specifying search range limits, low-to-high transition edge and
high-to-low transition edge found criterion, and number of
comparison outcomes in a trial comprising multiple tests specified
as proof of a low-to-high transition edge or as proof of a
high-to-low transition edge; computing initial values for trial
parameters using the search range limits, wherein the trial
parameters comprise: low-to-high band limits for a low-to-high
trial and a low-to-high trial value, high-to-low band limits for a
high-to-low trial and a high-to-low trial value, and number of high
indicating comparison outcomes from an assumed previous trial;
specifying the low-to-high transition edge and the high-to-low
transition edge as not found; if low-to-high transition edge not
found: executing the low-to-high trial on the electronic component
resulting in various low and high indicating comparison outcomes
and adjusting part of the trial parameter values based on results
of executing the low-to-high trial; if high-to-low transition edge
not found: executing the high-to-low trial on the electronic
component resulting in various low and high indicating comparison
outcomes and adjusting another part of the trial parameter values
based on results of executing the high-to-low trial; if the results
of the low-to-high trial meet the low-to-high transition edge found
criterion: specifying the low-to-high transition edge as found; if
the results of the high-to-low trial meet the high-to-low
transition edge found criterion: specifying the high-to-low
transition edge as found; if either low-to-high or high-to-low
transition edge not found: adjusting still another part of the
trial parameter values based on results of the above executed
trials and repeating the above beginning with the condition if
low-to-high transition edge not found; and storing the final trial
parameter values.
9. The computer readable memory device as recited in claim 8, the
instructions further comprising: prior to executing the low-to-high
trial, ensuring that the electronic component is in its low state;
and prior to executing the high-to-low trial, ensuring that the
electronic component is in its high state.
10. The computer readable memory device as recited in claim 8,
wherein the low-to-high transition edge found criterion and the
high-to-low transition edge found criterion depend upon a value
specified for a resolution limit of the search.
11. The computer readable memory device as recited in claim 10, the
instructions further comprising: if the absolute difference between
upper and lower low-to-high band limits for the low-to-high trial
is less than the resolution limit of the search, marking the
low-to-high transition edge as found; and if the absolute
difference between upper and lower high-to-low band limits for the
high-to-low trial is less than the resolution limit of the search,
marking the high-to-low transition edge as found.
12. The computer readable memory device as recited in claim 8, the
instructions further comprising: computing the low-to-high trial
value based on the upper and lower low-to-high band limits; and
computing the high-to-low trial value based on the upper and lower
high-to-low band limits.
13. The computer readable memory device as recited in claim 12,
wherein if either the upper low-to-high band limit does not equal
the upper high-to-low band limit or if the lower low-to-high band
limit does not equal the lower high-to-low band limit, the computed
low-to-high trial value is equal to one-half the sum of the upper
low-to-high band limit and the lower low-to-high band limit and the
computed high-to-low trial value is equal to one-half the value of
the upper high-to-low band limit subtracted from the lower
high-to-low band limit.
14. The computer readable memory device as recited in claim 12,
wherein if the upper low-to-high band limit equals the upper
high-to-low band limit and if the lower low-to-high band limit
equals the lower high-to-low band limit, the computed low-to-high
trial value is equal to the sum of the lower low-to-high band limit
and one-third the quantity of the lower low-to-high band limit
subtracted from the upper low-to-high band limit and the computed
high-to-low trial value is equal to the sum of the lower
high-to-low band limit and two-thirds the quantity of the lower
high-to-low band limit subtracted from the upper high-to-low band
limit.
15. A method for testing an electronic component, comprising:
specifying search range limits and low-to-high transition edge and
high-to-low transition edge found criterion; computing initial
values for trial parameters using the search range limits, wherein
the trial parameters comprise: low-to-high band limits for a
low-to-high trial and a low-to-high trial value and high-to-low
band limits for a high-to-low trial and a high-to-low trial value;
specifying the low-to-high transition edge and the high-to-low
transition edge as not found; if low-to-high transition edge not
found: ensuring that the electronic component is in its low state,
executing the low-to-high trial on the electronic component
resulting in various low and high indicating comparison outcomes,
and adjusting part of the trial parameter values based on results
of executing the low-to-high trial; if high-to-low transition edge
not found: ensuring that the electronic component is in its high
state executing the high-to-low trial on the electronic component
resulting in various low and high indicating comparison outcomes,
and adjusting another part of the trial parameter values based on
results of executing the high-to-low trial; if the results of the
low-to-high trial meet the low-to-high transition edge found
criterion: specifying the low-to-high transition edge as found; if
the results of the high-to-low trial meet the high-to-low
transition edge found criterion: specifying the high-to-low
transition edge as found; if either low-to-high or high-to-low
transition edge not found: adjusting still another part of the
trial parameter values based on results of the above executed
trials and repeating the above beginning with the condition if
low-to-high transition edge not found; and storing the final trial
parameter values.
16. The method as recited in claim 15, wherein the low-to-high
transition edge found criterion and the high-to-low transition edge
found criterion depend upon a value specified for a resolution
limit of the search.
17. The method as recited in claim 16, further comprising: if the
absolute difference between upper and lower low-to-high band limits
for the low-to-high trial is less than the resolution limit of the
search, marking the low-to-high transition edge as found; and if
the absolute difference between upper and lower high-to-low band
limits for the high-to-low trial is less than the resolution limit
of the search, marking the high-to-low transition edge as
found.
18. The method as recited in claim 15, further comprising:
computing the low-to-high trial value based on the upper and lower
low-to-high band limits; and computing the high-to-low trial value
based on the upper and lower high-to-low band limits.
19. A computer readable memory device having stored thereon
computer program instructions executable by the computer to perform
a method for testing an electronic component, the instructions
comprising: specifying search range limits and low-to-high
transition edge and high-to-low transition edge found criterion;
computing initial values for trial parameters using the search
range limits, wherein the trial parameters comprise: low-to-high
band limits for a low-to-high trial and a low-to-high trial value
and high-to-low band limits for a high-to-low trial and a
high-to-low trial value; specifying the low-to-high transition edge
and the high-to-low transition edge as not found; if low-to-high
transition edge not found: ensuring that the electronic component
is in its low state, executing the low-to-high trial on the
electronic component resulting in various low and high indicating
comparison outcomes, and adjusting part of the trial parameter
values based on results of executing the low-to-high trial; if
high-to-low transition edge not found: ensuring that the electronic
component is in its high state, executing the high-to-low trial on
the electronic component resulting in various low and high
indicating comparison outcomes, and adjusting another part of the
trial parameter values based on results of executing the
high-to-low trial; if the results of the low-to-high trial meet the
low-to-high transition edge found criterion: specifying the
low-to-high transition edge as found; if the results of the
high-to-low trial meet the high-to-low transition edge found
criterion: specifying the high-to-low transition edge as found; if
either low-to-high or high-to-low transition edge not found:
adjusting still another part of the trial parameter values based on
results of the above executed trials and repeating the above
beginning with the condition if low-to-high transition edge not
found; and storing the final trial parameter values.
20. The computer readable memory device as recited in claim 19,
wherein the low-to-high transition edge found criterion and the
high-to-low transition edge found criterion depend upon a value
specified for a resolution limit of the search.
21. The computer readable memory device as recited in claim 20, the
instructions further comprising: if the absolute difference between
upper and lower low-to-high band limits for the low-to-high trial
is less than the resolution limit of the search, marking the
low-to-high transition edge as found; and if the absolute
difference between upper and lower high-to-low band limits for the
high-to-low trial is less than the resolution limit of the search,
marking the high-to-low transition edge as found.
22. The computer readable memory device as recited in claim 19, the
instructions further comprising: computing the low-to-high trial
value based on the upper and lower low-to-high band limits; and
computing the high-to-low trial value based on the upper and lower
high-to-low band limits.
Description
BACKGROUND
[0001] Determining the range of signal levels at which an
electronic component switches from one state to another in the
presence of noise is typically a time consuming task. Current
methods for determining this range for electronic components such
as comparators often employ pairs of linear searches. One such
search begins by running a set of tests at an input signal level
for which the results are known to indicate that the component is
in a first state for all of the tests of the set and runs
successive sets of tests at increased input signal levels until the
results indicate that the component is in a second state for a
preselected number of the tests in the current set. The other
search begins by running a set of tests at an input signal level
for which the results are known to indicate that the component is
in the second state for all of the tests of the set and runs
successive sets of tests at decreased input signal levels until the
results indicate that the component is in the first state for a
preselected number of the tests in the current set. The searches
begin by setting a signal level a short distance away from the
expected "comparator trip point" and running a pattern that
performs a set of N comparisons in anticipation of obtaining either
"all fail" results for one direction of incrimination of the input
signal or "all pass" results for the other direction of
incrimination of the input signal. If either of these conditions
occurs, the signal level is incremented in the appropriate
direction and the test pattern is run again for another set of N
comparisons. These actions are repeated until one or more of the
set of comparisons no longer yields the same result (a "fail" or a
"pass") as at the start of the search.
[0002] Linear searches are typically time consuming. The speed of
the search can be increased by decreasing the span and/or precision
of the search. However, if it is preferred to find the comparator
trip region over a reasonably wide range so that the set point
accuracy can be quantified and if it is preferred to find the
bounds of the comparator trip region precisely so that comparison
noise can be quantified, a large number of search steps will
typically be required. The situation is compounded if the
comparator comprises a number of channels rather than just one.
SUMMARY
[0003] In a representative embodiment, a method for testing an
electronic component is disclosed. The method comprises connecting
the electronic component to a test machine; specifying search range
limits, low-to-high transition edge and high-to-low transition edge
found criterion, and number of outcomes in a trial comprising
multiple tests specified as proof of low-to-high transition or as
high-to-low transition; computing values for initial trial
parameters; if low-to-high transition edge not found: executing a
low-to-high trial and adjusting trial parameter values based on
results of step executing low-to-high trial; if high-to-low
transition edge not found: executing high-to-low trial; and if
either low-to-high or high-to-low transition edge not found:
adjusting trial parameter values based on results of step executing
high-to-low trial and repeating above steps beginning with the step
having the condition if low-to-high transition edge has not been
found. The trial parameters comprise low-to-high band limits for a
low-to-high trial and a low-to-high trial value, high-to-low band
limits for a high-to-low trial and a high-to-low trial value, and
number of high indicating comparison outcomes, wherein the initial
number is for an assumed previous trial.
[0004] In another representative embodiment, a computer readable
memory device is disclosed. The computer readable memory device
embodies a computer program of instructions executable by the
computer for testing an electronic component. The instructions
comprise connecting the electronic component to a test machine;
specifying search range limits, low-to-high transition edge and
high-to-low transition edge found criterion, and number of outcomes
in a trial comprising multiple tests specified as proof of
low-to-high transition or as high-to-low transition; computing
values for initial trial parameters; if low-to-high transition edge
not found: executing a low-to-high trial and adjusting trial
parameter values based on results of step executing low-to-high
trial; if high-to-low transition edge not found: executing
high-to-low trial; and if either low-to-high or high-to-low
transition edge not found: adjusting trial parameter values based
on results of step executing high-to-low trial and repeating above
steps beginning with the step having the condition if low-to-high
transition edge has not been found. The trial parameters comprise
low-to-high band limits for a low-to-high trial and a low-to-high
trial value, high-to-low band limits for a high-to-low trial and a
high-to-low trial value, and number of high indicating comparison
outcomes, wherein the initial number is for an assumed previous
trial.
[0005] In still another representative embodiment, another method
for testing an electronic component is disclosed. The method
comprises connecting the electronic component to a test machine;
specifying search range limits and low-to-high transition edge and
high-to-low transition edge found criterion; computing values for
initial trial parameters; if low-to-high transition edge not found:
ensuring that the electronic component is in its low state,
executing a low-to-high trial, and adjusting trial parameter values
based on results of step executing low-to-high trial; if
high-to-low transition edge not found: ensuring that the electronic
component is in its high state and executing high-to-low trial; and
if either low-to-high or high-to-low transition edge not found:
adjusting trial parameter values based on results of step executing
high-to-low trial and repeating above steps beginning with the step
having the condition if low-to-high transition edge has not been
found. The trial parameters comprise low-to-high band limits for a
low-to-high trial and a low-to-high trial value and high-to-low
band limits for a high-to-low trial and a high-to-low trial
value.
[0006] In yet another representative embodiment, a computer
readable memory device is disclosed. The computer readable memory
device embodies a computer program of instructions executable by
the computer for testing an electronic component. The instructions
comprise connecting the electronic component to a test machine;
specifying search range limits and low-to-high transition edge and
high-to-low transition edge found criterion; computing values for
initial trial parameters; if low-to-high transition edge not found:
ensuring that the electronic component is in its low state,
executing a low-to-high trial, and adjusting trial parameter values
based on results of step executing low-to-high trial; if
high-to-low transition edge not found: ensuring that the electronic
component is in its high state and executing high-to-low trial; and
if either low-to-high or high-to-low transition edge not found:
adjusting trial parameter values based on results of step executing
high-to-low trial and repeating above steps beginning with the step
having the condition if low-to-high transition edge has not been
found. The trial parameters comprise low-to-high band limits for a
low-to-high trial and a low-to-high trial value and high-to-low
band limits for a high-to-low trial and a high-to-low trial
value.
[0007] Other aspects and advantages of the representative
embodiments presented herein will become apparent from the
following detailed description, taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The accompanying drawings provide visual representations
which will be used to more fully describe various representative
embodiments and can be used by those skilled in the art to better
understand them and their inherent advantages. In these drawings,
like reference numerals identify corresponding elements.
[0009] FIG. 1 is a block diagram of an electronic component
attached to a test machine as described in various representative
embodiments.
[0010] FIG. 2A is a drawing of a graph of the output state of the
component vs. applied stimulus in the absence of hysteresis and
noise.
[0011] FIG. 2B is a drawing of another graph of the output state of
the component vs. applied stimulus in the presence of hysteresis
and the absence of noise.
[0012] FIG. 2C is a drawing of still another graph of the output
state of the component vs. applied stimulus in the absence of
hysteresis and in the presence of noise as described in various
representative embodiments.
[0013] FIG. 2D is a drawing of yet another graph of the output
state of the component vs. applied stimulus in the absence of
hysteresis and in the presence of noise as described in various
representative embodiments.
[0014] FIG. 3 is a drawing of a flow chart of a method for
obtaining lower and upper transition level information as described
in various representative embodiments.
[0015] FIG. 4A is a drawing of an expansion of a block of the flow
chart of FIG. 3.
[0016] FIG. 4B is a drawing of an expansion of another block of the
flow chart of FIG. 3.
[0017] FIG. 5A is a drawing of an expansion of a block of the flow
chart of FIG. 4A.
[0018] FIG. 5B is a drawing of an expansion of a block of the flow
chart of FIG. 4B.
[0019] FIG. 6A is a drawing of still another expansion of a block
of the flow chart of FIG. 4A.
[0020] FIG. 6B is a drawing of still another expansion of a block
of the flow chart of FIG. 4B.
[0021] FIG. 7A is a drawing of an expansion of a block of the flow
chart of FIG. 6A.
[0022] FIG. 7B is a drawing of an expansion of a block of the flow
chart of FIG. 6B.
[0023] FIG. 8A is a drawing of an expansion of yet another block of
the flow chart of FIG. 4A.
[0024] FIG. 8B is a drawing of an expansion of yet another block of
the flow chart of FIG. 4B.
[0025] FIG. 9A is a drawing of an expansion of a block of the flow
chart of FIG. 8A.
[0026] FIG. 9B is a drawing of an expansion of another block of the
flow chart of FIG. 8A.
[0027] FIG. 9C is a drawing of an expansion of a block of the flow
chart of FIG. 8B.
[0028] FIG. 9D is a drawing of an expansion of another block of the
flow chart of FIG. 8B.
[0029] FIG. 10 is a drawing of an expansion of still another block
of the flow chart of FIG. 8A.
[0030] FIG. 11 is a drawing of an expansion of still another block
of the flow chart of FIG. 3.
DETAILED DESCRIPTION
[0031] As shown in the drawings for purposes of illustration, novel
techniques are disclosed herein for determining the range of signal
levels at which an electronic component such as a comparator
switches from one state to another in the presence of noise and/or
hysteresis. These techniques comprise a double-ended binary search
for the upper and lower limits of this range of signal levels. The
present search techniques are typically faster than previous
techniques which most often include a pair of linear searches.
[0032] In the following detailed description and in the several
figures of the drawings, like elements are identified with like
reference numerals.
[0033] FIG. 1 is a block diagram of an electronic component 100
attached to a test machine 105 as described in various
representative embodiments. In FIG. 1, the electronic component 100
has a first input 110, also referred to herein as a reference input
110, a second input 115, also referred to herein as a signal input
115, and an output 120. The choice of reference input 110 and
signal input 115 is arbitrary and may be reversed. The test machine
105 comprises a central processing unit (CPU) 125, interface
circuitry 127 and a memory 130. A software program 135, also
referred to herein as a program 135, is stored in the test machine
105 and is used for testing the electronic component 100. The
electronic component 100 is also referred to herein as component
100 and may be comparator 100. The assignment of the reference
input 110 to the negative polarity and the signal input 115 to the
positive polarity is arbitrary and may be reversed. The reference
input 110 may be attached to ground or any other appropriate
reference potential.
[0034] When a test is performed on the component 100, the software
program 135 is loaded into the central processing unit 125 from the
memory 230 and executed. Commands generated from the software
program 135 are transmitted to the interface circuitry 127 which
applies the appropriate stimuli to the inputs 110,115 of the
electronic component 100. The condition of the output 120 is then
returned to the interface circuitry 127 and subsequently to the
executing software program 135.
[0035] As used herein, the component 100 is an electronic or other
component 100 having two output states, a first state and a second
state, as detected at the output 120. The first state is referred
to herein as the low state and would typically indicate that the
output of the component is either a low voltage or low current. The
second state is referred to herein as the high state and would
typically indicate that the output of the component is either a
high voltage or high current.
[0036] FIG. 2A is a drawing of a graph 200 of the output state 205
of the component 100 vs. applied stimulus 210 in the absence of
hysteresis and noise. In the example of FIG. 2A the output of
component 100 is in a first state 215, also referred to herein as a
low state 215, at any applied stimulus 210 to the left of or less
than the transition stimulus 220. In contrast, the output of
component 100 is in a second state 225, also referred to herein as
a high state 225, at any applied stimulus 210 to the right of or
greater than the transition stimulus 220.
[0037] FIG. 2B is a drawing of another graph 230 of the output
state 205 of the component 100 vs. applied stimulus 210 in the
presence of hysteresis 250 and the absence of noise. In the example
of FIG. 2B when transitioning from a low applied stimulus 210 to a
high applied stimulus 210, the output of component 100 is in a
first state 215 until the applied stimulus 210 reaches the value of
the high hysteresis stimulus 235, at which value the output of
component 100 transitions to the second state 225. In contrast,
when transitioning from a high applied stimulus 210 to a low
applied stimulus 210, the output of component 100 is in the second
state 215 until the applied stimulus 210 reaches the value of the
low hysteresis stimulus 240, at which value the output of component
100 transitions to the first state 215.
[0038] FIG. 2C is a drawing of still another graph 260 of the
output state 205 of the component 100 vs. applied stimulus 210 in
the absence of hysteresis 250 and in the presence of noise as
described in various representative embodiments. In the
representative embodiment of FIG. 2C, noise 265 is shown
superimposed on the applied stimulus 210 at lower transition level
270 and superimposed on the applied stimulus 210 at higher
transition level 275. Note that the superposition of the noise 265
at lower point 280 will cause the output state 205 of the component
100 to be in its low state 215, whereas the other stimuli 210 in
the superposition will cause the output state 205 of the component
100 to be in its high state 225, and that the superposition of the
noise 265 at higher point 285 will cause the output state 205 of
the component 100 to be in its high state 225, whereas the other
stimuli 210 in the superposition will cause the output state 205 of
the component 100 to be in its low state 215.
[0039] The lower transition level 270 and the higher transition
level 275 or another pair of levels between those values are
determined by successively applying stimulus 210 to the component
100 in sets of tests wherein each set of tests comprises "N" tests
at a given stimulus 210, wherein the applied stimulus 210 is
dependent upon the particular set of tests being run. In this
process and as used herein, the lower transition level 270 is the
applied stimulus 210 at which all but one of the "N" tests in one
of the sets of tests indicates the output state 205 of the
component 100 to be in its low state 215 and in this process and as
used herein, the higher transition level 275 is the applied
stimulus 210 at which all but one of the "N" tests in another set
of the sets of tests indicates the output state 205 of the
component 100 to be in its high state 225.
[0040] FIG. 2D is a drawing of yet another graph 260 of the output
state 205 of the component 100 vs. applied stimulus 210 in the
absence of hysteresis 250 and in the presence of noise as described
in various representative embodiments. In the representative
embodiment of FIG. 2D, noise 265 is shown superimposed on the
(nominal) transition stimulus value 220. Note that the
superposition of the noise 265 at lower point 280 and at other
points of the superposition less than the (nominal) transition
stimulus value 220 will cause the output state 205 of the component
100 to be in its low state 215, whereas and that the superposition
of the noise 265 at higher point 285 and at other points of the
superposition greater than the (nominal) transition stimulus value
220 will cause the output state 205 of the component 100 to be in
its high state 225.
[0041] The method disclosed herein allows the user to set a
transition threshold which is the number of changed comparison
outcomes in a set of tests specified by the user to be proof of a
transition. Referring to FIGS. 2C and 2D, the user can seek the
lower transition level and upper transition level by using the
method disclosed herein with the transition threshold set to either
1 (FIG. 2D) or to N-1 (FIG. 2C). The user can also set the
transition threshold to any value between 1 and N-1 to find a pair
of stimulus levels between the upper transition level and lower
transition level that the user deems to be statistically
significant representations of transitions or that are otherwise of
interest to the user.
[0042] In addition to the search results just discussed, the method
disclosed herein will provide two values, All_Lo and All_Hi, which
lie just below the lower transition level 270 and just above the
upper transition level 275 respectively. These provide the user
with additional information about the transition region, especially
when the transition threshold is set to some value between 1 and
N-1.
[0043] In the absence of noise but in the presence of hysteresis
250, the low hysteresis stimulus 240 and the high hysteresis
stimulus 235 of FIG. 2B would correspond respectively to the lower
transition level 270 and the higher transition level 275 of FIGS.
2C and 2D.
[0044] The characteristics and discussions related to FIGS. 2B and
2C (or FIGS. 2B and 2D) can be combined for the case of the
presence of hysteresis 250 and the presence of noise 265.
[0045] FIG. 3 is a drawing of a flow chart of a method 300 for
obtaining lower and upper transition level information as described
in various representative embodiments. In the method 300 of FIG. 3,
values can be obtained for a low-to-high transition edge and a
high-to-low transition edge which can represent the lower and
higher transition levels 270,275 or can represent values between
the lower and higher transition levels 270,275 as selected by the
user. The flow chart of FIG. 3 is an overview of this process. Flow
charts of the details of various blocks of FIG. 3 will be described
in subsequent figures.
[0046] As used in the following, the term trial refers to a set of
tests; a low-to-high trial is a set of tests in which an input is
first applied to the component 100 to place its output 120 in the
low state 215 and then the input is changed to the low-to-high
trial value (L2H_Try); the low-to-high transition edge is the input
applied to the component 100 which will result in the number of
changed comparison outcomes specified by the user to be proof of a
transition when a low-to-high trial is performed; a high-to-low
trial is a set of tests in which an input is first applied to the
component 100 to place its output 120 in the high state 225 and
then the input is changed to the high-to-low trial value (H2L_Try);
and the high-to-low transition edge is the input applied to the
component 100 which will result in the number of changed comparison
outcomes specified by the user to be proof of a transition when a
high-to-low trial is performed. When the number of changed
comparison outcomes specified to be proof of a transition is set to
one, the low-to-high transition edge will represent the lower
transition level 270 and the high-to-low transition edge will
represent the higher transition level 275. When the number of
changed comparison outcomes specified to be proof of a transition
is set to one less than the number of comparisons in a set of
comparisons (or equal to the number of comparisons in a set), the
low-to-high transition edge will represent the higher transition
level 275 and the high-to-low transition edge will represent the
lower transition level 270. Other settings of the number of changed
comparison outcomes specified to be proof of a transition can be
used to obtain intermediate values between the lower and higher
transition levels 270,275. The low-to-high transition edge and the
high-to-low transition edge are two of the end results of the
process of FIG. 3.
[0047] In searching for the transition signal level for a
comparator 100 in the presence of noise and/or hysteresis, there is
not one answer as to where the transition occurs, but rather there
is a band of behavior that characterizes the comparator transition.
An objective of the following is to locate the upper and lower
limits of that band or a pair of intermediate points of interest
within that band. As such, there are 2 searches that have to be
conducted to find those 2 points. These two searches will be
conducted in combination by performing alternating trials rather
than performing one search to completion to find one point and then
performing the other search to completion to find the other point.
Whenever the results of any one of those trials affect the
parameters for any subsequent trial whether for the low-to-high
transition edge or the high-to-low transition edge, any affected
search parameters will be updated. In the early stages of the
search, typically the parameters governing the selection of trial
values for both the low-to-high transition edge and the high-to-low
transition edge will be dependent upon the results of each trial.
In other words, after a single set of comparisons is run two sets
of search parameters will be updated. Near the end of the process,
however, the results for a set of comparisons of the high-to-low
search will only affect the high-to-low search parameters, and the
results for a set of comparisons of the low-to-high search will
only affect the low-to-high search parameters. So, the searches
become independent near their ends as the remaining search ranges
of the two searches cease to overlap.
[0048] Decisions are made based on the number of comparisons that
yield a transition and the number that do not. As an example, if a
set of high-to-low comparisons reads all low, the low-to-high
search will be updated to bring the lower end of the low-to-high
search range up equal to the value that was just tried, and the
high-to-low search will be updated to bring the high-to-low lower
value up equal to the value that was just tried. Then the
low-to-high search is performed using a previously computed trial
signal level. And, if the results of the low-to-high trial are all
high, the upper limit of the high-to-low search will be updated to
the trial value for the low-to-high search, and the upper limit of
the low-to-high search will be updated to the trial value for the
low-to-high search.
[0049] In block 305, the electronic component 100 is attached to
the test machine 105 as for example in FIG. 1. Block 305 then
transfers control to block 310.
[0050] In block 310, values for various search parameters which are
fixed for the determinations of FIG. 3 are specified by the user.
These parameters include the following: [0051] (1) The lower limit
of the search range of the sets of tests to be performed LoLim,
[0052] (2) The upper limit of the search range of the sets of tests
to be performed HiLim, [0053] (3) The minimum search step which is
the resolution limit of the process Step, [0054] (4) The number of
comparisons N to be made for each set of tests also referred to
herein as the number of comparisons per set of tests, and [0055]
(5) The transition Threshold which is the number of comparison
outcomes in a set of tests specified by the user to be proof of a
transition. The number of "high" comparison outcomes in any given
trial whether a low-to-high trial or a high-to-low trial is
identified by the symbol "HiCnt", and the number of "low"
comparison outcomes in any given trial whether a low-to-high trial
or a high-to-low trial is identified by the symbol "LoCnt". Block
310 then transfers control to block 315.
[0056] In block 315, values for the initial search parameters are
computed. These search parameter values are adjustable during the
process and comprise values for the following: [0057] (1) The all
low state bias value All_Lo. The all low state bias value All_Lo is
a value of applied stimulus 210 adjusted such that the initial
state for a low-to-high trial is the low state 215. The all low
state bias value All_Lo is initially set equal to the lower limit
of the search range of the sets of tests to be performed LoLim.
[0058] (2) The all high state bias value All_Hi. The all high state
bias value All_Hi is a value of applied stimulus 210 adjusted such
that the initial state for all a high-to-low trial is the high
state 225. The all high state bias value All_Hi is initially set
equal to the upper limit of the search range of the sets of tests
to be performed HiLim. [0059] (3) The low-to-high lower limit
L2H_Lo. The low-to-high lower limit L2H_Lo is the lower limit of
the low-to-high band used to search for the transition edge for
low-to-high transitions. The low-to-high lower limit L2H_Lo is one
of the values used to compute a new trial value for a low-to-high
trial. The low-to-high lower limit L2H_Lo is initially set equal to
the lower limit of the search range of the sets of tests to be
performed LoLim. [0060] (4) The low-to-high upper limit L2H_Hi. The
low-to-high upper limit L2H_Hi is the upper limit of the
low-to-high band used to search for the transition edge for
low-to-high transitions. The low-to-high upper limit L2H_Hi is one
of the values used to compute a new trial value for a low-to-high
trial. The low-to-high upper limit L2H_Hi is initially set equal to
the upper limit of the search range of the sets of tests to be
performed HiLim. The low-to-high lower limit L2H_Lo and the
low-to-high upper limit L2H_Hi are collectively referred to as the
low-to-high band limits L2H_Lo, L2H_Hi. [0061] (5) The high-to-low
lower limit H2L_Lo. The high-to-low lower limit H2L_Lo is the lower
limit of the high-to-low band used to search for the transition
edge for high-to-low transitions. The high-to-low lower limit
H2L_Lo is one of the values used to compute a new trial value for a
high-to-low trial. The high-to-low lower limit H2L_Lo is initially
set equal to the lower limit of the search range of the sets of
tests to be performed LoLim. [0062] (6) The high-to-low upper limit
H2L_Hi. The high-to-low upper limit H2L_Hi is the upper limit of
the high-to-low band used to search for the transition edge for
high-to-low transitions. The high-to-low upper limit H2L_Hi is one
of the values used to compute a new trial value for a high-to-low
trial. The high-to-low upper limit H2L_Hi is initially set equal to
the upper limit of the search range of the sets of tests to be
performed HiLim. The high-to-low lower limit H2L_Lo and the
high-to-low upper limit H2L_Hi are collectively referred to as the
high-to-low band limits H2L_Lo, H2L_Hi. [0063] (7) The low-to-high
trial value L2H_Try. The low-to-high trial value L2H_Try is the
applied stimulus 210 to which the input of the component 100 is
changed when executing a low-to-high trial. The low-to-high trial
value L2H_Try is initially set equal to a value between the lower
limit of the search range of the sets of tests to be performed
LoLim and the upper limit of the search range of the sets of tests
to be performed HiLim. A good choice for the initial low-to-high
trial value L2H_Try is [LoLim+(1/3)*(HiLim-LoLim)]. [0064] (8) The
high-to-low trial value H2L_Try. The high-to-low trial value
H2L_Try is the applied stimulus 210 to which the input of the
component 100 is changed when executing a high-to-low trial. The
high-to-low trial value H2L_Try is initially set equal to a value
between the lower limit of the search range of the sets of tests to
be performed LoLim and the upper limit of the search range of the
sets of tests to be performed HiLim. A good choice for the initial
high-to-low trial value H2L_Try is [HiLim-(1/3)*(HiLim-LoLim)].
These choices for the initial low-to-high trial value L2H_Try and
the initial high-to-low trial value H2L_Try split the band between
the lower limit of the search range of the sets of tests to be
performed LoLim and the upper limit of the range of the sets of
tests to be performed HiLim into three equal increments. [0065] (9)
The number of comparison outcomes indicating "high" HiCnt. At this
point, the number of comparison outcomes indicating "high" HiCnt is
that number from an "assumed" previous trial. The number of
comparison outcomes indicating "high" HiCnt is initially set equal
to any positive integer, for example the number one. Various
appropriate software program 135 control flags can also be
set/cleared as needed at this point in the process. For example, a
low-to-high "found" flag and a high-to-low "found" flag can be
cleared. A criterion that can be used for finding the low-to-high
transition edge and that can be used for finding the high-to-low
transition edge depends upon the value specified for the minimum
search step. In particular, the low-to-high transition edge could
be considered found if the absolute difference between upper and
lower low-to-high band limits L2H_Hi, L2H_Lo for the low-to-high
trial is less than the minimum search step and the high-to-low
transition edge could be considered found if the absolute
difference between upper and lower high-to-low band limits H2L_Hi,
H2L_Lo for the high-to-low trial is less than the minimum search
step. Block 315 then transfers control to block 320.
[0066] In block 320, a comparison trial for the low-to-high
transition edge is executed. The details of this trial are
described more fully in the description associated with FIG. 4A and
related figures. Block 320 then transfers control to block 325.
[0067] In block 325, a comparison trial for the high-to-low
transition edge is executed. The details of this trial are
described more fully in the description associated with FIG. 4B and
related figures. Block 325 then transfers control to block 330.
[0068] The order of the low-to-high trial of block 320 and the
high-to-low trial of block 325 is arbitrary and may be reversed.
One data update operation, updating of the "other" trial value if
invalidated by the first trial's results, must remain with the
first of the two trials, and setting of LoCnt to a nonzero value in
block 315 is needed it the high-to-low trial is first.
[0069] In block 330, if values for both the low-to-high transition
edge and the high-to-low transition edge have been found the search
is complete and block 330 transfers control to block 340.
Otherwise, block 330 transfers control to block 335. The
low-to-high transition edge is the L2H_Try after which the
difference between the low-to-high upper limit L2H_Hi and the
low-to-high lower limit L2H_Lo becomes less than or equal to the
minimum search Step, i.e., (L2H_Hi-L2H_Lo)<=Step. The
high-to-low transition edge is the H2L_Try after which the
difference between the high-to-low upper limit H2L_Hi and the
high-to-low lower limit H2L_Lo becomes less than or equal to the
minimum search Step, i.e., (H2L_Hi-H2L_Lo)<=Step. Appropriate
flags can be set in block 330 to indicate whether or not the
low-to-high transition edge and/or the high-to-low transition edge
have been found. Such flags can be useful in controlling the
operation of the method.
[0070] In block 335, new trial value(s) are computed as
appropriate. The details of these computations for the new trial
value(s) are described more fully in the description associated
with FIG. 11. Block 335 then transfers control to block 320.
[0071] In block 340, the results of the above process are used.
Such use could include a comparison of the resultant low-to-high
transition edge and the resultant high-to-low transition edge to
the specifications for the type of component 100 tested and
discarding the component 100 if the low-to-high transition edge or
the high-to-low transition edge lies outside the limits of the
specifications. Such use could also include statistically analyzing
the resultant low-to-high transition edge and the resultant
high-to-low transition edge making appropriate process changes to
hopefully increase the fabrication yield of the component 100.
Block 340 then terminates the process.
[0072] FIG. 4A is a drawing of an expansion of a block of the flow
chart of FIG. 3. In FIG. 4A, the expanded block is block 320 which
is the step executing a trial for low-to-high transition edge.
Block 320 accepts control from block 315 of FIG. 3 and passes
control to block 405 in FIG. 4A.
[0073] In block 405, if a component bias will be needed at the
signal input 115 to obtain initial all low output indications for
starting the low-to-high trial, block 405 transfers control to
block 410. The details of block 405 are shown in FIG. 5A. Otherwise
block 405 transfers control to block 415. Block 405 with its
details in FIG. 5A is present to compensate for the presence of
hysteresis. In such a situation, it is first necessary to ensure,
by force if necessary, that the electronic component 100 is in the
low state 215 which is accomplished by the application of an
appropriate bias. The effect of this bias is checked and, if
necessary, the bias value adjusted at each occurrence of block 320
due to the fact that random fluctuations or drift in the system may
result in a bias that is no longer of an appropriate level.
[0074] In block 410, a component bias is applied to the signal
input 115 to obtain initial all low comparison results for starting
the low-to-high trial. The details of block 410 are shown in FIG.
6A. Block 410 then transfers control to block 415.
[0075] In block 415, if the low-to-high search is complete block
415 exits block 320 transferring control to block 325. Otherwise,
block 415 transfers control to block 420.
[0076] In block 420, the low-to-high trial is executed. In
executing the low-to-high trial, the numbers of comparison results
indicating high and low (respectively HiCnt and LoCnt) are set
equal to zero. Then the value of the signal input 115 is set to the
low-to-high trial value (L2H_Try) and a set of comparisons is
performed by making separate observations of the value of the
output 120 of the component 100. With each comparison
(observation), if the output 120 of the component 100 is in the
high state 225, then the number of results indicating high (HiCnt)
is incremented by one, while if the output 120 of the component 100
is in the low state 225, then the number of results indicating low
(LoCnt) is incremented by one. Block 420 then transfers control to
block 425.
[0077] In block 425, the search limit parameters are updated per
the results of the low-to-high trial of block 420. The details of
this update of the search limit parameter(s) are described more
fully in the description associated with FIG. 8A. Block 425 then
exits block 320 transferring control to block 325.
[0078] FIG. 4B is a drawing of an expansion of another block of the
flow chart of FIG. 3. In FIG. 4B, the expanded block is block 325
which is the step executing a trial for high-to-low transition
edge. Block 325 accepts control from block 320 of FIG. 3 and passes
control to block 455 in FIG. 4B.
[0079] In block 455, if a component bias will be needed at the
signal input 115 to obtain initial all high output indications for
starting the high-to-low trial, block 455 transfers control to
block 460. The details of block 455 are shown in FIG. 5B. Otherwise
block 455 transfers control to block 465. Block 455 with its
details in FIG. 5B is present to compensate for the presence of
hysteresis. In such a situation, it is first necessary to ensure,
by force if necessary, that the electronic component 100 is in the
high state 225 which is accomplished by the application of an
appropriate bias. The effect of this bias is checked and, if
necessary, the bias value adjusted at each occurrence of block 325
due to the fact that random fluctuations or drift in the system may
result in a bias that is no longer of an appropriate level.
[0080] In block 460, a component bias is applied to the signal
input 115 to obtain initial all high comparison results for
starting the high-to-low trial. The details of block 460 are shown
in FIG. 6B. Block 460 then transfers control to block 465.
[0081] In block 465, if the high-to-low search is complete block
465 exits block 325 transferring control to block 330. Otherwise,
block 465 transfers control to block 470.
[0082] In block 470, the high-to-low trial is executed. In
executing the high-to-low trial, the numbers of comparison results
indicating high and low (HiCnt and LoCnt, respectively) are set
equal to zero. Then the value of the signal input 115 is set to the
high-to-low trial value (H2L_Try), and a set of comparisons is
performed by making separate observations of the value of the
output 120 of the component 100. With each comparison
(observation), if the output 120 of the component 100 is in the
high state 225, then the number of results indicating high (HiCnt)
is incremented by one, while if the output 120 of the component 100
is in the low state 225, then the number of results indicating low
(LoCnt) is incremented by one. Block 470 then transfers control to
block 475.
[0083] In block 475, the search limit parameters are updated per
the results of the high-to-low trial of block 470. The details of
this update of the search limit parameter(s) are described more
fully in the description associated with FIG. 8B. Block 475 then
exits block 325 transferring control to block 320.
[0084] FIG. 5A is a drawing of an expansion of a block of the flow
chart of FIG. 4A. In FIG. 5A, the expanded block is block 405 which
is the decision step that asks whether the low-to-high trial needs
biasing.
[0085] Block 405 accepts control from the input of block 320 of
FIG. 4A and passes control to block 505 in FIG. 5A.
[0086] In block 505, if all the results of the last trial are in
the low state 215, i.e., HiCnt=0, block 505 transfers control to
the output of block 405 labeled "NO" shown in FIG. 4A as well as
FIG. 5A. Otherwise, block 505 transfers control to block 510.
[0087] In block 510, if the low-to-high transition edge has been
found, i.e., the low-to-high search is complete, block 510
transfers control to the output of block 405 labeled "NO" shown in
FIG. 4A as well as FIG. 5A. Otherwise, block 510 transfers control
to the output of block 405 labeled "YES" shown in FIG. 4A as well
as FIG. 5A. A criterion that can be used for finding the
low-to-high transition edge depends upon the value specified for
the minimum search step. In particular, the low-to-high transition
edge could be considered found if the absolute difference between
upper and lower low-to-high band limits L2H_Hi, L2H_Lo for the
low-to-high trial is less than the minimum search step. If this or
an appropriate criterion is met, the low-to-high transition edge
270,275 is marked as found.
[0088] FIG. 5B is a drawing of an expansion of a block of the flow
chart of FIG. 4B. In FIG. 5B, the expanded block is block 455 which
is the decision step that asks whether the high-to-low trial needs
biasing.
[0089] Block 455 accepts control from the input of block 325 of
FIG. 4B and passes control to block 555 in FIG. 5B.
[0090] In block 555, if all the results of the last trial are in
the high state 225, i.e., LoCnt=0, block 555 transfers control to
the output of block 455 labeled "NO" shown in FIG. 4B as well as
FIG. 5B. Otherwise, block 555 transfers control to block 560.
[0091] In block 560, if the high-to-low transition edge has been
found, i.e., the high-to-low search is complete, block 560
transfers control to the output of block 455 labeled "NO" shown in
FIG. 4B as well as FIG. 5B. Otherwise, block 560 transfers control
to the output of block 455 labeled "YES" shown in FIG. 4B as well
as FIG. 5B. A criterion that can be used for finding the
high-to-low transition edge depends upon the value specified for
the minimum search step. In particular, the high-to-low transition
edge could be considered found if the absolute difference between
upper and lower high-to-low band limits H2L_Hi, H2L_Lo for the
high-to-low trial is less than the minimum search step. If this or
an appropriate criterion is met, the high-to-low transition edge
270,275 is marked as found.
[0092] FIG. 6A is a drawing of still another expansion of a block
of the flow chart of FIG. 4A. In FIG. 6A, the expanded block is
block 410 which is the block for applying the component bias needed
at the signal input 115 to obtain initial all low comparison
results for starting the low-to-high trial. Block 410 accepts
control from block 405 of FIG. 4A and passes control to block 605
in FIG. 6A.
[0093] In block 605, if any result from the last set of comparisons
is in the high state 225, i.e., HiCnt>0, block 605 transfers
control to block 610. Otherwise, block 605 transfers control to
block 415 in FIG. 4A.
[0094] In block 610, a set of comparisons is executed using the
current value of All_Lo. Block 610 then transfers control to block
615.
[0095] In block 615, if any result of the last set of comparisons
is in the high state 225, i.e., HiCnt>0, block 615 transfers
control to block 620. Otherwise, block 615 transfers control to
block 415 in FIG. 4A.
[0096] In block 620, if the all low state bias value All_Lo is
equal to the lower limit of the search range of the sets of tests
to be performed, LoLim, block 620 transfers control to block 415 in
FIG. 4A. Otherwise, block 620 transfers control to block 625. Note
that the all low state bias value All_Lo will not be lowered below
the lower limit of the search range of the sets of tests to be
performed, LoLim.
[0097] In block 625, the value of the all low state bias value
All_Lo is adjusted lower by the minimum search step but will not be
lowered below the lower limit of the search range of the sets of
tests to be performed, LoLim. The details of block 625 are shown in
FIG. 7A. Block 625 then transfers control to block 610.
[0098] FIG. 6B is a drawing of still another expansion of a block
of the flow chart of FIG. 4B. In FIG. 6B, the expanded block is
block 460 which is the block for applying the component bias needed
at the signal input 115 to obtain initial all high comparison
results for starting the high-to-low trial. Block 460 accepts
control from block 455 of FIG. 4B and passes control to block 655
in FIG. 6B.
[0099] In block 655, if any of result from the last set of
comparisons is in the low state 215, i.e., LoCnt>0, block 655
transfers control to block 660. Otherwise, block 655 transfers
control to block 465 in FIG. 4B.
[0100] In block 660, a set of comparisons is executed using the
current value of All_Hi. Block 660 then transfers control to block
665.
[0101] In block 665, if any result of the last set of comparisons
is in the low state 215, i.e., LoCnt>0, block 665 transfers
control to block 670. Otherwise, block 665 transfers control to
block 465 in FIG. 4B.
[0102] In block 670, if the all high state bias value All_Hi is
equal to the higher limit of the search range of the sets of tests
to be performed, HiLim, block 670 transfers control to block 465 in
FIG. 4B. Otherwise, block 670 transfers control to block 675. Note
that the all high state bias value All_Hi will not be raised above
the upper limit of the search range of the sets of tests to be
performed, HiLim.
[0103] In block 675, the value of the all high state bias value
All_Hi is adjusted higher by the minimum search step but will not
be raised above the upper limit of the search range of the sets of
tests to be performed, HiLim. The details of block 675 are shown in
FIG. 7B. Block 675 then transfers control to block 660.
[0104] FIG. 7A is a drawing of an expansion of a block of the flow
chart of FIG. 6A. In FIG. 7A, the expanded block is block 625 which
is the block for adjusting the value of the all low state bias
value All_Lo lower. Block 625 accepts control from block 620 of
FIG. 6A and passes control to block 705 in FIG. 7A.
[0105] In block 705, if the value of the all low state bias value
All_Lo is greater than the lower limit of the search range of the
sets of tests to be performed LoLim plus the value of the minimum
search step, block 705 transfers control to block 710. Otherwise,
block 705 transfers control to block 715.
[0106] In block 710, the all low state bias value All_Lo is
decreased by the value of the minimum search step. Block 710 then
transfers control to block 610 in FIG. 6A.
[0107] In block 715, the all low state bias value All_Lo is set
equal to the lower limit of the search range of the sets of tests
to be performed LoLim. Block 715 then transfers control to block
610 in FIG. 6A.
[0108] FIG. 7B is a drawing of an expansion of a block of the flow
chart of FIG. 6B. In FIG. 7B, the expanded block is block 675 which
is the block for adjusting the value of the all high state bias
value All_Hi higher. Block 675 accepts control from block 670 of
FIG. 6B and passes control to block 755 in FIG. 7B.
[0109] In block 755, if the value of the all high state bias value
All_Hi is less than the upper limit of the search range of the sets
of tests to be performed HiLim minus the value of the minimum
search step, block 755 transfers control to block 760. Otherwise,
block 755 transfers control to block 765.
[0110] In block 760, the all high state bias value All_Hi is
increased by the value of the minimum search step. Block 760 then
transfers control to block 660 in FIG. 6B.
[0111] In block 765, the all high state bias value All_Hi is set
equal to the upper limit of the search range of the sets of tests
to be performed HiLim. Block 765 then transfers control to block
660 in FIG. 6B.
[0112] FIG. 8A is a drawing of an expansion of yet another block of
the flow chart of FIG. 4A. In FIG. 8A, the expanded block is block
425 which is the block in which the search limit parameters are
updated based on results of a low-to-high trial.
[0113] The flow chart of FIG. 8A contains three alternative update
scenarios. After the execution of each low-to-high trial, one of
three results are possible as follows: (1) so few high results were
obtained that the trial value is clearly below the transition range
the user is searching for, (2) so few low results were obtained
that the trial value is clearly above the transition range that the
user is looking for, and (3) the mix of high and low results is
such that it cannot be stated that the trial value is clearly below
or clearly above the transition range and that the trial value is
therefore somewhere in between the edges of the transition range.
The first of these possible results is used by blocks 805 and 807
in updating search parameter values. The second is used by blocks
810 and 812 in updating search parameter values. While the third is
used by blocks 815, 817, 820, and 822 in updating search parameter
values. Note that block 807 is expanded in FIG. 9A and block 812 is
expanded in FIG. 9B.
[0114] Block 425 accepts control from block 420 of FIG. 4A and
passes control to block 805 in FIG. 8A.
[0115] In block 805, if the number of "high" comparison outcomes
HiCnt in the previous trial is less than the transition threshold
that is specified to be proof of a transition, block 805 transfers
control to block 807. Otherwise, block 805 transfers control to
block 810.
[0116] In block 807, values for the low-to-high lower limit L2H_Lo
and the high-to-low lower limit H2L_Lo are adjusted based on the
current values for the low-to-high trial value L2H_Try, the
low-to-high lower limit L2H_Lo and the high-to-low lower limit
H2L_Lo. The details of these computations for the new values of the
low-to-high lower limit L2H_Lo and the high-to-low lower limit
H2L_Lo are described more fully in the description associated with
FIG. 9A. Block 807 addresses the case in which the lower edge of
the transition zone in which the transition can be assumed to occur
based on the predefined value for the transition threshold lies
above the low-to-high trial value L2H_Try for the previous trial.
Block 807 then transfers control to block 825.
[0117] In block 810, if the number of "low" comparison outcomes
LoCnt in the previous trial is less than the transition threshold
that is specified to be proof of a transition, block 810 transfers
control to block 812. Otherwise, block 810 transfers control to
block 815.
[0118] In block 812, values for the low-to-high higher limit L2H_Hi
and the high-to-low higher limit H2L_Hi are adjusted based on the
current values for the low-to-high trial value L2H_Try, the
low-to-high higher limit L2H_Hi and the high-to-low higher limit
H2L_Hi. The details of these computations for the new values of the
low-to-high higher limit L2H_Hi and the high-to-low higher limit
H2L_Hi are described more fully in the description associated with
FIG. 9B. Block 812 addresses the case in which the upper edge of
the transition zone in which the transition can be assumed to occur
based on the predefined value for the transition threshold lies
below the low-to-high trial value L2H_Try for the previous trial.
Block 812 then transfers control to block 825.
[0119] In block 815, if the current value of the low-to-high trial
value L2H_Try is less than the current value of the low-to-high
upper limit L2H_Hi, block 815 transfers control to block 817.
Otherwise, block 815 transfers control to block 820.
[0120] Blocks 815, 817, 820, and 822 address the case in which the
low-to-high trial value L2H_Try for the previous trial is assumed
to lie above the lower edge of the transition zone in which the
transition can be assumed to occur based on the predefined value
for the transition threshold and below the upper edge of the
transition zone in which the transition can be assumed to occur
again based on the predefined value for the transition
threshold.
[0121] In block 817, the value for the low-to-high higher limit
L2H_Hi is set equal to the value of the low-to-high trial value
L2H_Try for the previous trial. Block 817 then transfers control to
block 820.
[0122] In block 820, if the current value of the low-to-high trial
value L2H_Try is greater than the current value of the high-to-low
lower limit H2L_Lo, block 820 transfers control to block 822.
Otherwise, block 820 transfers control to block 825.
[0123] In block 822, the value for the high-to-low lower limit
H2L_Lo is set equal to the value of the low-to-high trial value
L2H_Try for the previous trial. Block 822 then transfers control to
block 825.
[0124] In block 825, if the current value of the high-to-low trial
value H2L_Try is invalidated, block 825 transfers control to block
827. The details of the determination as to the validity of the
high-to-low trial value H2L_Try are described more fully in the
description associated with FIG. 10. Otherwise, block 825 transfers
control to block 830.
[0125] In block 827, the value for the high-to-low trial value
H2L_Try is set equal to the mean of the current values for the
high-to-low upper limit H2L_Hi and the high-to-low lower limit
H2L_Lo. Block 827 then transfers control to block 830.
[0126] In block 830, if the number of "high" comparison outcomes
HiCnt in the previous trial is equal to zero, block 830 transfers
control to block 835. Otherwise, block 830 transfers control to
block 840.
[0127] In block 835, if the current value of the low-to-high trial
value L2H_Try is greater than the current value of the all low
state bias value All_Lo, block 835 transfers control to block 837.
Otherwise, block 835 transfers control to block 325 in FIG. 3 (see
also block 425 in FIG. 4A).
[0128] In block 837, the value for the all low state bias value
All_Lo is set equal to the current value of the low-to-high trial
value L2H_Try. Block 837 then transfers control to block 325 in
FIG. 3 (see also block 425 in FIG. 4A). Block 837 is reached by way
of blocks 830 and 835 with the result in block 837 that the all low
state bias value All_Lo is pulled in, i.e., pulled up. This is done
so that when the component 100 is biased, the application of
signals over wide ranges is not forced. Progressively smaller and
smaller signal movements are applied as the search progresses so
that as little noise as possible is introduced into the system.
[0129] In block 840, if the number of "low" comparison outcomes
LoCnt in the previous trial is equal to zero, block 840 transfers
control to block 845. Otherwise, block 840 transfers control to
block 325 in FIG. 3 (see also block 425 in FIG. 4A).
[0130] In block 845, if the current value of the low-to-high trial
value L2H_Try is less than the current value of the all high state
bias value All_Hi, block 845 transfers control to block 847.
Otherwise, block 845 transfers control to block 325 in FIG. 3 (see
also block 425 in FIG. 4A).
[0131] In block 847, the value for the all high state bias value
All_Hi is set equal to the current value of the low-to-high trial
value L2H_Try. Block 847 then transfers control to block 325 in
FIG. 3 (see also block 425 in FIG. 4A). Block 847 is reached by way
of blocks 840 and 845 with the result in block 847 that the all
high state bias value All_Hi is pulled in, i.e., pulled down. This
is done so that when the component 100 is biased, the application
of signals over wide ranges is not forced. Progressively smaller
and smaller signal movements are applied as the search progresses
so that as little noise as possible is introduced into the
system.
[0132] FIG. 8B is a drawing of an expansion of yet another block of
the flow chart of FIG. 4B. In FIG. 8B, the expanded block is block
475 which is the block in which the search limit parameters are
updated based on results of a high-to-low trial.
[0133] The flow chart of FIG. 8B contains three alternative update
scenarios. After the execution of each high-to-low trial, one of
three results are possible as follows: (1) so few low results were
obtained that the trial value is clearly above the transition range
the user is searching for, (2) so few high results were obtained
that the trial value is clearly below the transition range that the
user is looking for, and (3) the mix of high and low results is
such that it cannot be stated that the trial value is clearly below
or clearly above the transition range and that the trial value is
therefore somewhere in between the edges of the transition range.
The first of these possible results is used by blocks 855 and 857
in updating search parameter values. The second is used by blocks
860 and 862 in updating search parameter values. While the third is
used by blocks 865, 867, 870, and 872 in updating search parameter
values. Note that block 857 is expanded in FIG. 9C and block 862 is
expanded in FIG. 9D.
[0134] Block 475 accepts control from block 470 of FIG. 4B and
passes control to block 855 in FIG. 8B.
[0135] In block 855, if the number of "low" comparison outcomes
LoCnt in the previous trial is less than the transition threshold
that is specified to be proof of a transition, block 855 transfers
control to block 857. Otherwise, block 855 transfers control to
block 860.
[0136] In block 857, values for the low-to-high higher limit L2H_Hi
and the high-to-low higher limit H2L_Hi are adjusted based on the
current values for the high-to-low trial value H2L_Try, the
low-to-high higher limit L2H_Hi and the high-to-low higher limit
H2L_Hi. The details of these computations for the new values of the
low-to-high higher limit L2H_Hi and the high-to-low higher limit
H2L_Hi are described more fully in the description associated with
FIG. 9C. Block 857 addresses the case in which the higher edge of
the transition zone in which the transition can be assumed to occur
based on the predefined value for the transition threshold lies
below the high-to-low trial value H2L_Try for the previous trial.
Block 857 then transfers control to block 880.
[0137] In block 860, if the number of "high" comparison outcomes
HiCnt in the previous trial is less than the transition threshold
that is specified to be proof of a transition, block 860 transfers
control to block 862. Otherwise, block 860 transfers control to
block 865.
[0138] In block 862, values for the low-to-high lower limit L2H_Lo
and the high-to-low lower limit H2L_Lo are adjusted based on the
current values for the high-to-low trial value H2L_Try, the
low-to-high lower limit L2H_Lo and the high-to-low lower limit
H2L_Lo. The details of these computations for the new values of the
low-to-high lower limit L2H_Lo and the high-to-low lower limit
H2L_Lo are described more fully in the description associated with
FIG. 9D. Block 862 addresses the case in which the upper edge of
the transition zone in which the transition can be assumed to occur
based on the predefined value for the transition threshold lies
above the high-to-low trial value H2L_Try for the previous trial.
Block 862 then transfers control to block 880.
[0139] In block 865, if the current value of the high-to-low trial
value H2L_Try is less than the current value of the low-to-high
upper limit L2H_Hi, block 865 transfers control to block 867.
Otherwise, block 865 transfers control to block 870.
[0140] Blocks 865, 867, 870, and 872 address the case in which the
high-to-low trial value H2L_Try for the previous trial is assumed
to lie above the lower edge of the transition zone in which the
transition can be assumed to occur based on the predefined value
for the transition threshold and below the upper edge of the
transition zone in which the transition can be assumed to occur
again based on the predefined value for the transition
threshold.
[0141] In block 867, the value for the low-to-high higher limit
L2H_Hi is set equal to the value of the high-to-low trial value
H2L_Try for the previous trial. Block 867 then transfers control to
block 870.
[0142] In block 870, if the current value of the high-to-low trial
value H2L_Try is greater than the current value of the high-to-low
lower limit H2 .mu.L_Lo, block 870 transfers control to block 872.
Otherwise, block 870 transfers control to block 880.
[0143] In block 872, the value for the high-to-low lower limit
H2L_Lo is set equal to the value of the high-to-low trial value
H2L_Try for the previous trial. Block 872 then transfers control to
block 880.
[0144] In block 880, if the number of "low" comparison outcomes
LoCnt in the previous trial is equal to zero, block 880 transfers
control to block 885. Otherwise, block 880 transfers control to
block 890.
[0145] In block 885, if the current value of the high-to-low trial
value H2L_Try is less than the current value of the all high state
bias value All_Hi, block 885 transfers control to block 887.
Otherwise, block 885 transfers control to block 330 in FIG. 3 (see
also block 475 in FIG. 4B).
[0146] In block 887, the value for the all high state bias value
All_Hi is set equal to the current value of the high-to-low trial
value H2L_Try. Block 887 then transfers control to block 330 in
FIG. 3 (see also block 475 in FIG. 4B). Block 887 is reached by way
of blocks 880 and 885 with the result in block 887 that the all
high state bias value All_Hi is pulled in, i.e., pulled down. This
is done so that when the component 100 is biased, the application
of signals over wide ranges is not forced. Progressively smaller
and smaller signal movements are applied as the search progresses
so that as little noise as possible is introduced into the
system.
[0147] In block 890, if the number of "high" comparison outcomes
HiCnt in the previous trial is equal to zero, block 890 transfers
control to block 895. Otherwise, block 890 transfers control to
block 330 in FIG. 3 (see also block 475 in FIG. 4B).
[0148] In block 895, if the current value of the high-to-low trial
value H2L_Try is greater than the current value of the all low
state bias value All_Lo, block 895 transfers control to block 897.
Otherwise, block 895 transfers control to block 330 in FIG. 3 (see
also block 475 in FIG. 4B).
[0149] In block 897, the value for the all low state bias value
All_Lo is set equal to the current value of the high-to-low trial
value H2L_Try. Block 897 then transfers control to block 330 in
FIG. 3 (see also block 475 in FIG. 4B). Block 897 is reached by way
of blocks 890 and 895 with the result in block 897 that the all low
state bias value All_Lo is pulled in, i.e., pulled up. This is done
so that when the component 100 is biased, the application of
signals over wide ranges is not forced. Progressively smaller and
smaller signal movements are applied as the search progresses so
that as little noise as possible is introduced into the system.
[0150] FIG. 9A is a drawing of an expansion of a block of the flow
chart of FIG. 8A. In FIG. 9A, the expanded block is block 807 which
is the block in which the values for the low-to-high lower limit
L2H_Lo and the high-to-low lower limit H2L_Lo are adjusted based on
the current values for the low-to-high trial value L2H_Try, the
low-to-high lower limit L2H_Lo and the high-to-low lower limit
H2L_Lo. Block 807 accepts control from the output of block 805
labeled "YES" as shown in FIG. 8A and passes control to block 905
in FIG. 9A.
[0151] In block 905, if the current value of the low-to-high trial
value L2H_Try is greater than the current value of the low-to-high
lower limit L2H_Lo, block 905 transfers control to block 910.
Otherwise, block 905 transfers control to block 915.
[0152] In block 910, the value for the low-to-high lower limit
L2H_Lo is set equal to the current value of the low-to-high trial
value L2H_Try. Block 910 then transfers control to block 915.
[0153] In block 915, if the current value of the low-to-high trial
value L2H_Try is greater than the current value of the high-to-low
lower limit H2L_Lo, block 915 transfers control to block 920.
Otherwise, block 915 transfers control to block 825 in FIG. 8A.
[0154] In block 920, the value for the high-to-low lower limit
H2L_Lo is set equal to the current value of the low-to-high trial
value L2H_Try. Block 920 then transfers control to block 825 in
FIG. 8A.
[0155] FIG. 9B is a drawing of an expansion of another block of the
flow chart of FIG. 8A. In FIG. 9B, the expanded block is block 812
which is the block in which the values for the low-to-high higher
limit L2H_Hi and the high-to-low higher limit H2L_Hi are adjusted
based on the current values for the low-to-high trial value
L2H_Try, the low-to-high higher limit L2H_Hi and the high-to-low
higher limit H2L_Hi. Block 812 accepts control from the output of
block 810 labeled "YES" as shown in FIG. 8A and passes control to
block 925 in FIG. 9B.
[0156] In block 925, if the current value of the low-to-high trial
value L2H_Try is less than the current value of the low-to-high
higher limit L2H_Hi, block 925 transfers control to block 930.
Otherwise, block 925 transfers control to block 935.
[0157] In block 930, the value for the low-to-high higher limit
L2H_Hi is set equal to the current value of the low-to-high trial
value L2H_Try. Block 930 then transfers control to block 935.
[0158] In block 935, if the current value of the low-to-high trial
value L2H_Try is less than the current value of the high-to-low
higher limit H2L_Hi, block 935 transfers control to block 940.
Otherwise, block 935 transfers control to block 825 in FIG. 8A.
[0159] In block 940, the value for the high-to-low higher limit
H2L_Hi is set equal to the current value of the low-to-high trial
value L2H_Try. Block 940 then transfers control to block 825 in
FIG. 8A.
[0160] FIG. 9C is a drawing of an expansion of a block of the flow
chart of FIG. 8B. In FIG. 9C, the expanded block is block 857 which
is the block in which the values for the low-to-high higher limit
L2H_Hi and the high-to-low higher limit H2L_Hi are adjusted based
on the current values for the high-to-low trial value H2L_Try, the
low-to-high higher limit L2H_Hi and the high-to-low higher limit
H2L_Hi. Block 857 accepts control from the output of block 855
labeled "YES" as shown in FIG. 8B and passes control to block 955
in FIG. 9C.
[0161] In block 955, if the current value of the high-to-low trial
value H2L_Try is less than the current value of the low-to-high
higher limit L2H_Hi, block 955 transfers control to block 960.
Otherwise, block 955 transfers control to block 965.
[0162] In block 960, the value for the low-to-high higher limit
L2H_Hi is set equal to the current value of the high-to-low trial
value H2L_Try. Block 960 then transfers control to block 965.
[0163] In block 965, if the current value of the high-to-low trial
value H2L_Try is less than the current value of the high-to-low
higher limit H2L_Hi, block 965 transfers control to block 970.
Otherwise, block 965 transfers control to block 880 in FIG. 8B.
[0164] In block 970, the value for the high-to-low higher limit
H2L_Hi is set equal to the current value of the high-to-low trial
value H2L_Try. Block 970 then transfers control to block 880 in
FIG. 8B.
[0165] FIG. 9D is a drawing of an expansion of another block of the
flow chart of FIG. 8B. In FIG. 9D, the expanded block is block 862
which is the block in which the values for the low-to-high lower
limit L2H_Lo and the high-to-low lower limit H2L_Lo are adjusted
based on the current values for the high-to-low trial value
H2L_Try, the low-to-high lower limit L2H_Lo and the high-to-low
lower limit H2L_Lo. Block 862 accepts control from the output of
block 860 labeled "YES" as shown in FIG. 8B and passes control to
block 975 in FIG. 9D.
[0166] In block 975, if the current value of the high-to-low trial
value H2L_Try is greater than the current value of the low-to-high
lower limit L2H_Lo, block 975 transfers control to block 980.
Otherwise, block 975 transfers control to block 985.
[0167] In block 980, the value for the low-to-high lower limit
L2H_Lo is set equal to the current value of the high-to-low trial
value H2L_Try. Block 980 then transfers control to block 985.
[0168] In block 985, if the current value of the high-to-low trial
value H2L_Try is greater than the current value of the high-to-low
lower limit H2L_Lo, block 985 transfers control to block 990.
Otherwise, block 985 transfers control to block 880 in FIG. 8B.
[0169] In block 990, the value for the high-to-low lower limit
H2L_Lo is set equal to the current value of the high-to-low trial
value H2L_Try. Block 990 then transfers control to block 880 in
FIG. 8B.
[0170] FIG. 10 is a drawing of an expansion of still another block
of the flow chart of FIG. 8A. In FIG. 10, the expanded block is
block 825 which is the block in which the determination as to the
validity of the high-to-low trial value H2L_Try is made. Block 825
accepts control from the output of block 820 labeled "NO" and from
the outputs of blocks 807,812, and 822 as shown in FIG. 8A and
passes control to block 1010 in FIG. 10.
[0171] In block 1010, if the current value of the high-to-low trial
value H2L_Try is greater than the current value of the high-to-low
lower limit H2L_Lo, block 1010 transfers control to block 1020.
Otherwise, block 1010 transfers control to block 1030.
[0172] In block 1020, if the current value of the high-to-low trial
value H2L_Try is less than the current value of the high-to-low
higher limit H2L_Hi, block 1020 transfers control to block 830 in
FIG. 8A. Otherwise, block 1020 transfers control to block 1030.
[0173] In block 1030, if the current value of the high-to-low trial
value H2L_Try equals the current value of the all high state bias
value All_Hi, block 1030 transfers control to block 830 in FIG. 8A.
Otherwise, block 1030 transfers control to block 827 in FIG.
8A.
[0174] FIG. 11 is a drawing of an expansion of still another block
of the flow chart of FIG. 3. In FIGS. 3 and 11, the expanded block
is block 335 which is the block in which new trial value(s) are
computed as appropriate. Block 335 accepts control from the output
of block 330 labeled "NO" as shown in FIG. 3 and passes control to
block 1105 in FIG. 11.
[0175] In block 1105, if the current value of the low-to-high lower
limit L2H_Lo equals the current value of the high-to-low lower
limit H2L_Lo, block 1105 transfers control to block 1110.
Otherwise, block 1105 transfers control to block 1120.
[0176] In block 1110, if the current value of the low-to-high
higher limit L2H_Hi equals the current value of the high-to-low
higher limit H2L_Hi, block 1110 transfers control to block 1115.
Otherwise, block 1110 transfers control to block 1120.
[0177] In block 1115, a Boolean parameter Identical_Tries is set to
TRUE. The Boolean parameter Identical_Tries is used to indicate
that the new trial values to be calculated (the low-to-high trial
value L2H_Try and the high-to-low trial value H2L_Try) could be
equal unless action is taken. Thus, it is possible for two trials
to be run consecutively using the same trial value which is
wasteful of resources. Block 1115 then transfers control to block
1125.
[0178] In block 1120, the Boolean parameter Identical_Tries is set
to FALSE. Block 1120 then transfers control to block 1125.
[0179] In block 1125, if the low-to-high state has been found,
block 1125 transfers control to block 1145. Otherwise, block 1125
transfers control to block 1130.
[0180] In block 1130, the low-to-high trial value L2H_Try is set
equal to the mean of the current value of the low-to-high lower
limit L2H_Lo and the current value of the low-to-high higher limit
L2H_Hi. Block 1130 then transfers control to block 1135.
[0181] In block 1135, if the Boolean parameter Identical_Tries is
set to TRUE, block 1135 transfers control to block 1140. Otherwise,
block 1135 transfers control to block 1145.
[0182] In block 1140, the low-to-high trial value L2H_Try is
lowered by one-third of the difference between the current value of
the low-to-high trial value L2H_Try and the current value of the
low-to-high lower limit L2H_Lo. Thus, the value for the low-to-high
trial value L2H_Try is separated from the soon to be computed
high-to-low trial value H2L_Try rather than perform two tests at
the same trial signal level. Block 1140 then transfers control to
block 1145.
[0183] In block 1145, if the high-to-low state has been found,
block 1145 transfers control to block 320 on FIG. 3. Otherwise,
block 1145 transfers control to block 1150.
[0184] In block 1150, the high-to-low trial value H2L_Try is set
equal to the mean of the current value of the high-to-low lower
limit H2L_Lo and the current value of the high-to-low higher limit
H2L_Hi. Block 1150 then transfers control to block 1155.
[0185] In block 1155, if the Boolean parameter Identical_Tries is
set to TRUE, block 1155 transfers control to block 1160. Otherwise,
block 1155 transfers control to block 320 on FIG. 3.
[0186] In block 1160, the high-to-low trial value H2L_Try is raised
by one-third of the difference between the current value of the
high-to-low upper limit H2L_Hi and the high-to-low trial value
H2L_Try. Thus, the value for the high-to-low trial value H2L_Try is
separated from what would have been the low-to-high trial value
L2H_Try rather than perform two tests at the same trial signal
level. Block 1160 then transfers control to block 320 on FIG.
3.
[0187] As is the case, in many data-processing products, the
systems described above may be implemented as a combination of
hardware and software components. Moreover, the functionality
required for use of the representative embodiments may be embodied
in computer-readable media (such as floppy disks, conventional hard
disks, DVDs, CD-ROMs, Flash ROMs, nonvolatile ROM, and RAM among
others) to be used in programming an information-processing
apparatus (e.g., the test machine 105 comprising the elements shown
in FIG. 1 among others) to perform in accordance with the
techniques so described.
[0188] The term "program storage medium" is broadly defined herein
to include any kind of computer memory such as, but not limited to,
floppy disks, conventional hard disks, DVDs, CD-ROMs, Flash ROMs,
nonvolatile ROM, and RAM.
[0189] The central processing unit 125 of the test machine 105, can
be capable of running one or more of any commercially available
operating system such as DOS, various versions of Microsoft Windows
(Windows 95, 98, Me, 2000, NT, XP, or the like), Apple's MAC OS X,
UNIX, Linux, or other suitable operating system.
[0190] Representative embodiments disclosed herein can be
implemented as an application program which can be written using a
variety of programming languages including Visual Basic, C/C++,
assembler or any other commercially-available programming
tools.
[0191] In a representative embodiments of the methods described
herein efficient techniques are disclosed for determining the range
of signal levels at which an electronic component such as a
comparator switches from one state to another in the presence of
noise and/or hysteresis. These techniques comprise a double-ended
binary search for the upper and lower limits of this range of
signal levels. The present search techniques are typically faster
than previous techniques which most often include a pair of linear
searches.
[0192] The representative embodiments, which have been described in
detail herein, have been presented by way of example and not by way
of limitation. It will be understood by those skilled in the art
that various changes may be made in the form and details of the
described embodiments resulting in equivalent embodiments that
remain within the scope of the appended claims.
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