U.S. patent number 3,852,718 [Application Number 05/409,766] was granted by the patent office on 1974-12-03 for apparatus for interpreting numerically coded pulse groupings in a line.
This patent grant is currently assigned to Hayward H. Dutton, Joseph Schulein, Margaret A. Schulein. Invention is credited to Karl G. De Lyria.
United States Patent |
3,852,718 |
De Lyria |
December 3, 1974 |
APPARATUS FOR INTERPRETING NUMERICALLY CODED PULSE GROUPINGS IN A
LINE
Abstract
An electrical supervisory signaling system employing a plurality
of McCulloh-type pulse transmitters which are operable selectively
to transmit over a line one or more like groups, or "rounds," of
time-spaced, numerically coded pulses. Single-"round" and
multiple-"round" transmissions are used to indicate different
monitored conditions. Receiving these pulses in the system is an
interpreter which, through examining the time spacings between
successive pulses, both distinguishes the transmissions from the
different transmitters, and indicates whether a transmission from a
given transmitter contains one or more "rounds" of pulses.
BACKGROUND AND SUMMARY OF THE INVENTION This invention pertains to
an electrical supervisory signaling system of the type employing a
plurality of McCulloh-type pulse transmitters. More particularly,
it relates to an interpreter usable in such a system for
automatically and reliably sorting out and interpreting the various
transmissions therein of the different transmitters employed in the
system. A typical McCulloh-type transmitter includes a notched
rotary wheel which may be turned selectively by a motor, such as by
an electric or a spring-wound motor. The notches and lands in the
wheel, with the latter turning, alternately open and close an
associated electrical switch, which action is used to generate
electrical voltage pulses in a line, such as in a conventional
telephone line. The arrangement of notches and lands provided in
such a wheel defines a numerical pulse "code" for a transmitter. A
typical code includes a group, or "round," of pulses divided into
three sections, with each section containing one or more pulses. As
an illustration, one code might be 2-3-1, resulting in a pulse
group containing a first section including two time-spaced pulses,
a second section containing three time-spaced pulses, and a third
and final section containing a single pulse. A transmitter of the
type just generally described is often set up to operate in two
different modes so as to be able to respond to two different
monitored conditions. In one mode of operation, the transmitter
transmits but a single round of pulses, and in the other mode
transmits two or more rounds. To illustrate, a transmitter set up
to monitor the condition of a fire sprinkler system might be
arranged to transmit but a single round if a non-fire-induced break
occurs in the system, and more than one round in the event of the
system turning on to handle a fire. Further explaining what is
conventional, within a coded round of pulses, it is usually
intended that successive pulses within a section in the round be
spaced apart by one uniform preselected time, and that successive
sections in the round be spaced apart by another, longer
preselected uniform time. Further, it is normally the case that
successive rounds transmitted by a transmitter are spaced apart
longer than the spacings between successive sections within a
round. All of this practice, of course, is to aid in distinguishing
rounds, and in distinguishing pulse sections within a round. With
McCulloh-type transmitters, individual pulses normallly last
between about .25-1.5-seconds, with the spaces between adjacent
pulses in a section being the same width as the pulses. Further, it
is usually the case that the time spacing used between successive
sections in a round is about twice the spacing used between pulses
in a section. The same two-to-one relationship normally typifies
the length of the space between successive rounds as compared with
the length between successive sections in a round. Thus, the pulses
in a coded round might, for example, each be about 0.25-seconds
long, with the gaps between pulses in a section also being about
0.25-seconds, and the gaps between sections in the round being
about 0.5-seconds. Were the transmitter which is capable of
producing such a round operated so as to produce successive rounds,
the time spacings therebetween would typically be about 1-second
for the example just described. One of the problems with
transmitters of the type just outllined is that the pulse widths,
and the different pulse spacings, associated with a transmitter are
not uniform, even within the transmission of a single round of
pulses. This is partly due to the mechanical tolerances permitted
in the manufacture of a notched wheel in a transmitter, and also
partly due to the fact that the wheel when turned may not be
rotated at a constant speed. As a consequence, the electrical pulse
waveform transmitted by such a transmitter is not entirely
predictable, and can be difficult to interpret. A further problem
is that transmitters of the type outlined have typically been used
heretofore in systems wherein recording-type receivers, such as
rolled paper tape recorders, have been used. What is recorded by
such a recorder must be monitored by a person, and interpreted by
him so as to distinguish different codes that may be transmitted in
a system. Such an arrangement introduces considerable delay in
obtaining desired information, and is quite prone to errors. A
general object of the present invention, therefore, is to provide
novel means usable in a signaling system with transmitters of the
type above outlined to receive and interpret transmissions
therefrom in a manner avoiding the difficulties just mentioned.
More specifically, an object of the invention is to provide a novel
electrical interpreter which is capable of ignoring pulse width and
pulse spacing irregularities in the transmission from such a
transmitter, and which is further capable of accurately and
reliably distinguishing the coded transmissions of different
transmitters which may be used in a system. Still another object of
the invention is to provide such an interpreter which is capable of
determining whether the transmission from a given transmitter
includes, on the one hand, a single coded round of pulses, or on
the other hand, more than one round of pulses. According to a
preferred embodiment of the invention, an interpreter is proposed
which accomplishes the above-stated objectives through examining
major differences in the time spacings between successive pulses
transmitted over a line in a system, thus to determine the
beginnings and endings of different rounds, as well as the
beginnings and endings of different pulse sections in a round.
Included in the interpreter, for each transmitter employed in the
system with which the interpreter is used, is a programmed memory
capable of responding to, but only to, the coded transmission of
but one of the transmitters in the system. The interpreter of the
invention continuously, and without the need for human
intervention, monitors the signal conditions in a line in a system,
and essentially immediately reports on each transmission in the
system, with each such report specifically identifying which
transmitter has operated, and what information it transmitted.
These and other objects and advantages attained by the invention
will become more fully apparent as the description which follows is
read in conjunction with the accompanying drawings.
Inventors: |
De Lyria; Karl G. (Vancouver,
WA) |
Assignee: |
Dutton; Hayward H. (Vancouver,
WA)
Schulein; Joseph (Vancouver, WA)
Schulein; Margaret A. (Vancouver, WA)
|
Family
ID: |
23621871 |
Appl.
No.: |
05/409,766 |
Filed: |
October 25, 1973 |
Current U.S.
Class: |
340/534;
340/12.17; 340/286.01; 340/293 |
Current CPC
Class: |
G08B
25/045 (20130101) |
Current International
Class: |
G08B
25/04 (20060101); G08B 25/01 (20060101); G08b
025/00 () |
Field of
Search: |
;340/164R,167R,168R,293,213R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Yusko; Donald J.
Attorney, Agent or Firm: Kolisch, Hartwell, Dickinson &
Stuart
Claims
It is claimed and desired to secure by letters patent:
1. An interpreter for use in an electrical signaling system of the
type which includes a transmission line and a plurality of coded
signalers operatively connected to said line, each signaler being
operable selectively to produce and transmit over said line one or
more like-coded groups of time-spaced electrical pulses, with each
such group including a plurality of pulse sections each containing
one or more pulses depending upon the particular code associated
with the signaler, with the times between adjacent pulses in a
section under all circumstances being shorter than the times
between adjacent sections in a group, and with the latter-mentioned
times under all circumstances being shorter than the times between
successive groups produced by the signaler, said interpreter in
operative condition comprising
a code-reading circuit operatively coupled to said line and
constructed to read the particular code of each coded group of
pulses transmitted in the line,
a code-discriminating circuit for each different signaler in the
system, each operatively connected to said code-reading circuit and
operable to indicate a reading by the latter of the particular code
associated with the code-reading circuit's associated signaler,
a pulse-group-spacing-monitoring circuit operatively coupled to
said line and constructed to respond to the transmission therein of
coded groups of pulses, and to generate, following the completion
of such a group, a response of one type if another coded group of
pulses follows within a preselected time span, and a response of
another type if no such successive group follows within said
preselected time span, and
an output circuit for each code-discriminating circuit operatively
connected thereto and to said pulse-group-spacing-monitoring
circuit, each operable, with its associated code-discriminating
circuit indicating a reading of its associated code, to produce an
output signal of one type on said pulse-group-spacing-monitoring
circuit generating a response of said one type, and to produce an
output signal of another type on the pulse-group-spacing-monitoring
circuit generating a response of said other type,
each output circuit including means inhibiting the simultaneous
production thereby of both types of output signals.
2. The interpreter of claim 1 which further includes an input
circuit operatively connected between said line and said
code-reading and pulse-group-spacing-monitoring circuits for
processing pulses transmitted in the line for inputting into the
latter-mentioned two circuits, said input circuit being constructed
to generate, for each pulse transmitted by a signaler in the
system, a time-related, controlled-duration follower pulse.
3. The interpreter of claim 1, wherein said code-reading circuit
includes: a timing circuit for discerning and identifying the
different pulse sections in a coded group of pulses through
monitoring the time spacings between successive pulses in a group
to locate a spacing greater than that expected between adjacent
pulses in a section but less than that expected between adjacent
sections in a group; a read pulse generator operatively connected
to said timing circuit for generating a read pulse on the timing
circuit identifying a section in a group; a resettable pulse
counter operatively connected both to said line and to said read
pulse generator, constructed to count pulses transmitted in the
line, and to be reset to a zero-count condition on each occurrence
of a read pulse; and a resettable section counter operatively
connected to said read pulse generator for counting read pulses
generated thereby.
4. The interpreter of claim 3, wherein each code-discriminating
circuit comprises a memory programmed in accordance with the code
associated with the code-discriminating circuit, each memory being
operatively connected to said read pulse generator and to said
counters, and being operable to produce a sustained indication
following, but only following, receipt over said line of a group of
pulses coded in accordance with the code associated with the
memory.
5. The interpreter of claim 1, wherein said
pulse-group-spacing-monitoring circuit includes: a timing circuit
for discerning and identifying different successive coded groups of
pulses through monitoring the time spacings between successive
pulses transmitted in the line to locate a spacing greater than
that expected between adjacent sections in a group but less than
that expected between successive like groups transmitted by a
signaler; and an interval decision circuit operatively connected to
said timing circuit for following the intervals between successive
pulse group identifications by said timing circuit, said interval
decision circuit effecting generation by said
pulse-group-spacing-monitoring circuit of a response of said one
type on said timing circuit identifying the beginning of a new
pulse group within a preselected interval following its previous
identification of a pulse group, and effecting a response by said
pulse-group-spacing-monitoring circuit of said other type under all
other circumstances.
6. In an electrical signaling system of the type which includes a
transmission line, and a plurality of coded signalers operatively
connected to said line, each signaler being operable selectively to
produce and transmit over said line one or more like-coded groups
of time-spaced electrical pulses, with each such group including a
plurality of pulse sections each containing one or more pulses
depending upon the particular code associated with the signaler,
with the times between adjacent pulses in a section under all
circumstances being shorter than the times between adjacent
sections in a group, and with the latter-mentioned times under all
circumstances being shorter than the times between successive
groups produced by the signaler, an interpreter comprising
a code-reading circuit operatively coupled to said line and
constructed to read the particular code of each coded group of
pulses transmitted in the line,
a code-discriminating circuit for each different signaler in the
system, each operatively connected to said code-reading circuit and
operable to indicate a reading by the latter of the particular code
associated with the code-reading circuit's associated signaler,
a pulse-group-spacing-monitoring circuit operatively coupled to
said line and constructed to respond to the transmission therein of
coded groups of pulses, and to generate, following the completion
of such a group, a response of one type if another coded group of
pulses follows within a preselected time span, and a response of
another type if no such successive group follows within said
preselected time span, and
an output circuit for each code-discriminating circuit operatively
connected thereto and to said pulse-group-spacing-monitoring
circuit, each operable, with its associated code-discriminating
circuit indicating a reading of its associated code, to produce an
output signal of one type on said pulse-group-spacing-monitoring
circuit generating a response of said one type, and to produce an
output signal of another type on the pulse-group-spacing-monitoring
circuit generating a response of said other type,
each output circuit including means inhibiting the simultaneous
production thereby of both types of output signals.
Description
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified diagram partially showing a signaling system
employing McCulloh transmitters and a receiving interpreter as
contemplated by the present invention.
FIG. 2 is a block diagram illustrating details of the interpreter
used in the system of FIG. 1.
FIG. 3 is a block diagram illustrating, in greater detail, a
portion of the interpreter of FIG. 2.
And, FIGS. 4 and 5 are similar graphs illustrating, along a time
base, several different voltage waveforms which appear at different
points in the interpreter of FIG. 2 during two different modes of
operation of the interpreter.
DETAILED DESCRIPTION OF THE INVENTION
1. explanation of Terminology
Explaining briefly certain terminology which will be used in the
description which follows, various components shown in the drawings
operate in a response to a pair of voltage levels. More
specifically, one of these levels corresponds to a certain positive
voltage (typically about +5 volts) which will be referred to
hereinafter as a 1 state. The other level corresponds essentially
to ground, and will be called hereinafter a 0 state. A terminal or
a conductor having one of these voltage levels on it will be
referred to as being in, or as having on it, either a 1 or a 0
state.
2. Description of the Logic Gates Used
Among the components illustrated in the drawings which respond to
the two voltage levels just mentioned are certain logic gates. More
specifically, four different types of gates, all conventional in
construction, are employed. These are referred to as AND, NAND, OR
and NOR gates.
An AND gate functions as follows: with a 0 state on any input of
the gate, the output thereof is held in a 0 state; with all inputs
in 1 states, the output is placed also in a 1 state.
In a NAND gate: with a 0 state on any input, the output is held in
a 1 state; with all inputs in 1 states, the output is placed in a 0
state.
In an OR gate: if any input is in a 1 state, the output of the gate
is held also in a 1 state; if all inputs are in 0 states, then the
output is also in a 0 state.
Finally, a NOR gate functions whereby: if any input is in a 1
state, the output is held in a 0 state; if all inputs are placed in
0 states, then the output is placed in a 1 state.
The operations of other components shown in the drawings which
respond to these two voltage levels will be explained as such
components are encountered in the description which follows.
3. The Signaling System Generally
Turning now to the drawings, and referring first to FIG. 1,
indicated generally at 10 is what is referred to herein as a
conductive signaling system including remotely located transmitting
and receiving portions 12, 14, respectively, which are represented
in FIG. 1 as being separated by a dashed line 16. System 10 herein
is used for reporting fire status and sprinkler system status
information with respect to a plurality of facilities, such as
storage warehouses, that are located remote from the receiving
portion of the system. The term "fire status" is used herein to
mean whether or not a fire exists; and the term "sprinkler system
status" is intended to mean whether or not a sprinkler system is
operative.
Included in the transmitting portion of system 10 are a plurality
of conventional, electric-motor-driven McCulloh transmitters, or
signalers, such as the two shown in block form at 18, 20. Each such
transmitter is employed with respect to a different facility
herein, and each is set up to operate in either of two different
modes of operation. In one of these operating modes, a transmitter
produces a single round, or group, of coded pulses-- this being
done to indicate that the sprinkler system in the associated
facility has become inoperative. In the other operating mode, a
transmitter transmits, one after another, a plurality of rounds of
pulses to indicate that a fire exists at the associated facility.
The way in which the transmitters in system 10 are connected to
perform in such a manner is entirely conventional, and forms no
part of the present invention. In general terms, the transmitters
are suitably operatively connected to appropriate sensors which
monitor the selected conditions of interest, and which operate to
energize the motors in the transmitters to transmit the correct
number of rounds.
McCulloh transmitters and the like typically take two different
forms-- referred to as "normally open" and "normally closed"
transmitters. In a normally open transmitter, the switch which is
actuated by the wheel in the transmitter is normally open, and
produces pulses by successive closures of this switch with turning
of the wheel. Such transmitters, in a given system, are usually
connected in parallel with one another. A normally closed
transmitter is characterized by just the reverse operation, and in
a given system, such transmitters are usually connected in series.
The particular transmitters used in system 10 are of the normally
closed type, and in this system are connected in series with a
battery 22 (or some other suitable source of DC power) and the coil
24a of a relay 24. Relay 24 also includes a normally closed switch
24b which in FIG. 1 is shown open for a reason which will be
explained shortly.
Information in system 10 is transmitted over a suitable
two-conductor line, such as a conventional telephone line. The
particular telephone line used in system 10 includes conductors 26,
28. Conductor 26 connects directly with one side of switch 24b.
Conductor 28, which is grounded, connects with one side of a
battery (or other suitable DC power source) 30--the other side of
which is connected through a conductor 32 to the other side of
switch 24b. Conductor 26 is connected through a resistor 34 to
ground.
System 10 is shown in FIG. 1 with the switches in its transmitters
all closed. As a consequence, and because of the series connection
mentioned earlier, coil 24a is energized, and holds switch 24b
open. Under these circumstances, conductor 26 is essentially at
ground potential, or in a 0 state. With operation of a transmitter,
it will be evident that switch 24b is alternately closed and opened
to produce successive positive voltage square wave pulses (i.e., 1
states) on conductor 26.
The particular different transmitters in system 10 are constructed
to produce different coded rounds of pulses, with each round
containing three pulse sections. These pulse sections each include
on or more pulses. For example, transmitter 18 herein is associated
with the numerical code 2-3-1, and when operated to transmit a
round of pulses, transmits a round containing a first pulse section
containing two time-spaced pulses, a second pulse section
containing three time-spaced pulses, and a third section containing
a single pulse. Thus, the number 231 is printed in FIG. 1 on the
block representing transmitter 18, as an indication of its
associated code. Transmitter 20 is constructed to transmit rounds
with the code 1-4-3. Accordingly, the number 143 appears in the
block in FIG. 1 representing transmitter 20.
Each transmitter in system 10 is intended to transmit pulses having
a duration of 0.25-seconds, with successive pulses in a section in
a round separated by the same amount of time. It is further
intended that successive sections in a round be separated by
0.5-seconds, and that successive rounds (when a transmitter is
operated to produce a plurality of rounds) be separated by
1-second. However, because of the tolerance and operational speed
problems mentioned earlier, these times may actually vary within
about plus or minus 10 percent.
Considering for a moment FIG. 4, Graph A therein illustrates a
typical single round of coded pulses produced in conductor 26 by
operation of transmitter 18. As can be seen, this round includes
three pulse sections, indicated by the three brackets and
designated I, II, III. Section I contains two pulses 36, 38,
section II three pulses 40, 42, 44, and section III a single pulse
46. The reference character T.sub.1 indicates the nominal or
intended pulse width of 0.25-seconds. It will be recalled that this
same time is the nominal or intended time between pulses in a
section. The reference character T.sub.2 indicates the nominal or
intended time between pulse sections of 0.5-seconds.
In Graph A, an effort has been made to depict a round of pulses
wherein the times, as would be experienced in actual practice, do
not conform to the nominal or intended times. Thus, in section I,
pulse 36 is somewhat shorter than, and pulse 38 somewhat longer
than 0.25-seconds. The interval between these pulses is somewhat
longer than 0.25-seconds. In section II, pulse 40 is somewhat
shorter than, pulse 42 about equal to, and pulse 44 considerably
longer than, 0.25-seconds. The gap between pulses 40, 42 exceeds,
whereas the gap between pulses 42, 44 is less than, 0.25-seconds.
Pulse 46 in section III is shorter than 0.25-seconds. Considering
the intervals between the pulse sections, both of these intervals
are somewhat less than 0.5-seconds.
Returning to FIG. 1, included in the receiving portion of system 10
is a receiving interpreter, shown generally at 48, which is
constructed in accordance with the present invention. Interpreter
48 may be thought of, and is depicted in FIG. 1, as containing a
block of components 50 connected directly to conductors 26, 28, and
blocks, such as blocks 52, 54, connected to block 50, and each
associated particularly with a different one of the transmitters in
the system.
Bllocks 52, 54 herein are associated with transmitters 18, 20,
respectively, and accordingly, bear the code numbers 231, 143,
respectively. Block 52 is connected to block 50 through
multiple-conductor cables represented by the heavy lines shown at
56, 58. Block 54 is connected to block 50 through cable 56 and a
cable 60. Other blocks, like blocks 52, 54, are provided for the
other transmitters in the system.
Explaining very briefly, and only in very general terms, how system
10 operates, should a breakdown occur in the sprinkler system
located at the facility monitored by transmitter 18, this
transmitter is immediately operated to produce in conductor 26 a
single round of coded pulses, with the code 2-3-1. This
transmission is received by interpreter 48, which functions, as
will be explained in detail later, to interpret this transmission
correctly as being one from transmitter 18, and as comprising but a
single round of pulses. On determining that the transmission was
made by transmitter 18, and that it consists of a single round of
pulses, block 52, and only block 52, provides one type of an output
signal immediately indicating this situation.
In the case of a fire at the same location, transmitter 18 is
operated to produce multiple successive rounds of pulses which are
also received by the interpreter, and again interpreted thereby as
correctly coming from transmitter 18. Further, the interpreter
determines that in this case the transmission received comprises
multiple rounds of pulses, by which determination it ascertains
that what is being indicated by transmitter 18 is that there is a
fire. In this case, block 52, again alone, produces another type of
output signal to indicate this situation.
Similar operations take place with respect to transmissions made by
each other transmitter in system 10.
4. Details of the Interpreter
The overall construction of interpreter 48 is shown in FIGS. 2 and
3, and reference is now made particularly to these figures.
Included within block 50 in the interpreter, such block being
illustrated in dashed lines in FIG. 2, and shown in block form
therein, are an input circuit 62, three timers, or timing circuits,
64, 66, 68, a read pulse generator 70, a reset circuit 72, and a
pair of counters 74, 76 which are referred to herein respectively
as a pulse counter and a section counter. Also included within
block 50 are three two-input logic gates including two AND gates
78, 80, and a NOR gate 82.
Timer 64 is also referred to herein as a code pulse section timer,
timer 66 as a code pulse group timer, and timer 68 as an intergroup
interval timer. In addition, timer 64, generator 70, and counters
74, 76 are referred to collectively as a code-reading circuit, and
timer 68 along with gates 80, 82 are referred to collectively as an
interval decision circuit. Further, timers 66, 68 along with gates
80, 82 constitute a pulse-group-spacing-monitoring circuit.
Previously mentioned conductors 26, 28 are connected to the input
side of circuit 62--the output of this circuit being connected
through a conductor 84 to the input of timer 64, through conductor
84 and a conductor 86 to the input of timer 66, and through
conductors 84, 86 and a conductor 88 to the counting terminal of
counter 74. Connecting the output of timer 64 and the input of
generator 70 is a conductor 90. A conductor 92 connects with the
output of generator 70. Connecting conductor 92 with the input of
reset circuit 72 is a conductor 94. The output of this circuit is
connected through a conductor 96 to the upper input of gate 78. And
a lower input of gate 78 in connected via a conductor 98 to the
output of timer 66.
Further describing the interconnections existing between components
in block 50, gate 78 has its output connected via a conductor 100
to the counting terminal of counter 76. A conductor 102
interconnects conductor 100 and the reset terminal of counter 74.
Conductor 98 is connected through a conductor 104 to the input of
timer 68, and is connected through conductor 104 and a conductor
106 to the upper input of gate 80. The output of timer 68 is
coupled through a conductor 108 to the lower input of gate 82. The
lower and upper inputs of gates 80, 82, respectively, are connected
via conductors 110, 112, respectively, to conductors 108, 106,
respectively. The outputs of gates 80, 82 are connected to
conductors 114, 116, respectively.
Input circuit 62, timer 68, generator 70, and reset circuit 72
herein each comprise conventional monostable multivibrators.
Circuit 62 responds to a state change from 0 to 1 on conductor 26,
and on such a state change occurring, produces at its output a
positive, controlled-duration, square wave voltage pulse, called
herein a follower pulse, which lasts about 0.05-seconds. Timer 68,
generator 70 and reset circuit 72, on the other hand, respond to
state changes from 1 to 0 on their respective inputs to produce at
their outputs similar positive, controlled-duration, square wave
voltage pulses. In particular, timer 68 produces a pulse which
lasts about 0.75-seconds, and generator 70 and reset circuit 72
each produce a pulse which lasts about 0.015-seconds.
Timers 64, 66 are similar in construction-- each comprising a
conventional retriggerable monostable multivibrator. Each of these
timers responds to a state change from 0 to 1 on its input to
produce a 1 state at its output, which 1 state lasts throughout the
application of a 1 state at its input, plus an additional
predetermined time interval. More particularly, with the
application of a 1 state to the input of timer 64, the output of
this timer switches to a 1 state, and remains therein until about
0.6-seconds after removal of the 1 state from the input. Similarly,
with application of a 1 state to the input of timer 66, the output
of this timer switches to a 1 state, wherein it remains until about
1-second after removal of the 1 state from its input. The term
"retriggerable" as used herein respecting these timers means that a
timer may be held in a condition placing a 1 state on its output,
so long as successive 0 to 1 state changes recur on its input
before completion of the "time-out" interval for the timer
following the last preceding return of the input to a 0 state.
Counters 74, 76 are conventional decimal-output binary counters.
Counter 74 is constructed to count from 0-9, inclusive. This
counter includes ten separate output terminals (not specifically
shown in the drawings) each related to a different one of the ten
different counts which may be stored in the counter. To each of the
nine of these output terminals which are associated with the counts
1-9, inclusive, is connected a separate conductor-all of which
conductors are illustrated as a single heavy-line cable 118 in FIG.
2. With counter 74 in a zero-count condition, each of these nine
output terminals is in a 0 state, with the other terminal in a 1
state. The counter responds to each state change from 1 to 0 on its
counting terminal to change the count in the counter. For example,
with the counter in a zero-count condition, on the first such state
change occurring on the counting terminal, the counter places a 1
state on its single output terminal which is associated with the
count of "one"--all other output terminals then being in 0 states.
On the second 1 to 0 state change occurring on the counting
terminal, the counter places a 1 state on its output terminal
associated with the count of "two"--all other output terminals then
being in 0 states; and so on. A state change from 1 to 0 on its
reset terminal returns the counter to a zero-count condition.
Counter 76 is similar in construction and operation to counter 74,
except that counter 76 includes but three output terminals (not
specifically shown) associated with the counts 1-3 inclusive. To
each of these separate output terminals is connected a separate
conductor--all of which conductors are included within a cable
shown at 120 in FIG. 2. Counter 76 is normally in a condition
storing a count of "one," with a 1 state existing on its output
terminal associated with this count. Its other two output terminals
are normally in 0 states. With the first count thereafter made by
counter 76, a 1 state is placed on its output terminal associated
with the count of "two," and the other two output terminals are
placed in 0 states. Similarly, when the next count is recorded, a 1
state is placed on the output terminal associated with the count of
"three," and the other two output terminals are placed in 0 states.
On the next count being recorded, counter 76 returns a 1 state to
its output terminal associated with the count of "one"--the other
two output terminals then being placed in 0 states. Such operation
recurs in cycles with successive counts recorded by the
counter.
Continuing with a description of what is shown in FIG. 2, included
within previously mentioned block 52 (shown in dashed lines in FIG.
2) are a code latch circuit, or memory, 122, a code matrix 124, a
pair of alarm latch circuits 126, 128, and a pair of NOR gates 130,
132.
Circuit 122 and matrix 124 are referred to herein collectively as a
code-discriminating circuit. As will be more fully explained later,
this combined circuit is programmed herein to respond only to a
coded round of pulses transmitted by transmitter 18. As can be seen
in FIG. 2, circuit 126 is also referred to as a "Condition 1 Alarm
Latch Circuit," and circuit 128 as a "Condition 2 Alarm Latch
Circuit." These two circuits, along with gates 130, 132 comprise an
output circuit in interpreter 48. As will become apparent, circuit
126 and gate 130 are employed in the production of an output signal
to indicate a transmission from transmitter 18 consisting of but a
single round of pulses, whereas circuit 128 and gate 132 are
employed in effecting another type of output signal in the case of
such a transmission containing more than one round of pulses.
Previously mentioned conductors 92, 114, 116 are connected to input
sides of circuits 122, 128, 126, respectively. Also connected to
the input side of circuit 122 are cables 134, 136. As will be
explained more fullly shortly, cable 134 includes three conductors
connected to the output side of code matrix 124. Cable 136 includes
three conductors, each connected to a different one of the three
conductors previously mentioned in cable 120. A nine-conductor
cable 138 connects the input side of the code matrix with the nine
different conductors previously mentioned in cable 118.
The output of code latch circuit 122 is connected via a conductor
140 to the upper input of gate 130, and via conductor 140 and a
conductor 142 to the upper input of gate 132. Circuits 126, 129
each include a pair of outputs. The lower output of circuit 126 is
connected by a conductor 144 to the lower input of gate 130, and
also is connected through this conductor and a conductor 146 to the
upper output of circuit 128. The lower output of circuit 128
connects with the lower input of gate 132 through a conductor 148,
and connects through conductor 148 and a conductor 150 with the
upper output of circuit 126. Conductors 146, 148 constitute
inhibiting means herein. The outputs of gates 130, 132 are
connected to conductors 152, 154, respectively.
Connected with conductors 92, 114, 116, and extending downwardly
therefrom in FIG. 2 between blocks 50, 52, are conductors 156, 158,
160, respectively.
As a final correlation between FIGS. 1 and 2, the horizontal
portion of cable 56 shown in FIG. 1 includes those portions of
conductors 92, 114, 116, and of cables 118, 120, which extend
horizontally into block 50 in FIG. 2. The vertical portion of cable
56 in FIG. 1 includes conductors 156, 158, 160, and the vertical
portions of cables 118, 120, in FIG. 2. Cable 58 in FIG. 1 includes
those portions of conductors 92, 114, 116, and of cables 136, 138,
which extend into block 52 in FIG. 2.
Turning now to FIG. 3, this illustrates details of several of the
components shown within block 52 in FIG. 2. Code matrix 124 is
shown at the bottom of FIG. 3, and is depicted therein as a
rectangular grid of crossed conductors including three vertically
extending conductors 162, 164, 166, and nine horizontally extending
conductors 168a-168i, inclusive. Where these conductors cross in
the matrix, the presence of a black dot indicates a connection
between the two crossing conductors, and the absence of such a dot
indicates the absence of such a connection. Conductors 162, 164,
166 comprise the three conductors mentioned earlier which form
cable 134. Conductors 168a-168i comprise the nine conductors
mentioned earlier within cable 138.
Appearing to the right of the grid just described, adjacent the
right ends of conductors 168a-168i, is a column containing the
numbers 1-9, inclusive. These numbers have been included in the
drawing to indicate the associations between conductors 168a-168i
and the nine output terminals of pulse counter 74. In particular,
conductor 168a is associated with that output terminal of the pulse
counter which is placed in a 1 state with a count of "one" stored
in the counter; conductor 168b is associated with that output
terminal of the pulse counter on which a 1 state is placed with the
counter storing a count of "two"; and so on. Such 1 states on the
output terminals of the pulse counter result in 1 states also
beiing placed on the respective associated ones of conductors
168a-168i.
It will be apparent that with a matrix such as that just described,
programming is possible in accordance with the different codes that
may be used by transmitters, simply through selection of the three
locations where crossed wires in the matrix are connected. Matrix
124 is shown programmed for the code 2-3-1 which, of course, is
associated with transmitter 18. Thus, connections exist between
conductors 168b, 162, between conductors 168c, 164, and between
conductors 168a, 166.
Code latch circuit 122 includes four three-input NAND gates 170,
172, 174, 176, and three conventional set-reset circuits shown as
blocks 178, 180, 182.
The upper inputs of gates 170, 172, 174, are each connected as
shown to previously mentioned conductor 92. The middle inputs of
gates 170, 172, 174 are connected to conductors 184, 186, 188,
respectively, which are the three conductors previously mentioned
making up cable 136. The lower inputs of gates 170, 172, 174 are
connected to previously mentioned conductors 162, 164, 166
respectively.
Conductors 184, 186, 188 are each connected to a different one of
the three conductors previously mentioned within cable 120 (see
FIG. 2). More specifically, conductor 184 is connected to that
conductor in cable 120 which connects with the output terminal of
counter 76 that is placed in a 1 state with a count of "one" stored
in the counter; conductor 186 is connected to that conductor in
cable 120 which is connected to the output terminal of the counter
on which a 1 state is applied when the count of "two" is stored in
the counter; and, conductor 188 is connected to that conductor in
cable 120 which is connected to the other output terminal of
counter 76.
The outputs of gates 170, 172, 174 are connected to the set
terminals, marked S in FIG. 3, of circuits 178, 180, 182,
respectively. The reset terminals of these circuits, marked R, are
connected together to a suitable manual reset circuit (not shown)
which may be operated, as will later be explained, to effect
resetting of the circuits. The outputs of circuits 178, 180, 182
are connected as shown to the three inputs of gate 176. The output
of gate 176 is connected to previously mentioned conductor 140.
Considering briefly the operation of the set-reset circuits, with
such a circuit in a reset condition, a 0 state exists on its
output. On a state change from 1 to 0 occurring at the set terminal
of the circuit, the circuit is placed in a so-called set condition,
wherein its output is placed in a 1 state. This situation remains
until there is applied to the reset terminal in the circuit a state
change from 1 to 0, whereupon the output of the circuit is returned
to a 0 state.
Completing a description of what is shown in FIG. 3, previously
mentioned alarm latch circuits 126, 128 comprise conventional
electronic devices known as clocked-D flip-flops. Such a device
typically includes set, reset, clock, and D inputs, and Q and Q
outputs. In interpreter 48 herein, only four of such terminals are
used, these being the reset, clock and D inputs, and the Q output.
The reset inputs are marked by R, the clock inputs by C, the D
inputs simply by D, and the Q outputs by Q.
Explaining briefly how these devices perform, with such a device in
a so-called reset condition, a 1 state exists on the Q output. With
a state change of 0 to 1 occurring at the clock input, the Q output
is placed in the opposite of whatever state then exists on the D
input. For example, had a 0 state then been present on the D input,
the voltage state on the Q output (initially in a 1 state) would
remain unchanged. However, had the state on the D input been 1, the
Q output would switch to a 0 state. A state change from 0 to 1 on
the reset input returns the device to a reset condition.
The clock inputs of flip-flops 126, 128 are connected to previously
mentioned conductors 116, 114, respectively. The reset inputs are
suitably connected together to a suitable manual reset circuit like
that mentioned above in connection with circuits 178, 180, 182. The
D inputs of flip-flops 126, 128 are connected to conductors 150,
146, respectively, and the Q outputs of these devices are connected
to conductors 144, 148, respectively.
The contents of block 54 (see FIG. 1), and of the other such blocks
in interpreter 48 which are associated with transmitters in the
system other than transmitters 18, 20, are substantially identical
with those which have been described as being within block 52.
These other blocks differ from block 54 only with respect to the
specific programmings provided in the code matrices therein which
correspond to matrix 124. In other words, these other code matrices
are specially coded to relate to the specific codes associated with
the different transmitters in the system. For example, the code
maxtrix in block 54 is programmed in accordance with the code
1-4-3. Considering how such programming would affect connections
within a matrix, and referring back for a moment to FIG. 3, had
such a code been programmed into matrix 124, conductor 168a would
have been connected to conductor 162, conductor 168d to conductor
164, and conductor 168c to conductor 166.
Finally, also connected to all of the reset terminals in all of the
set-reset circuits and locked-D flip-flops in the interpreter, is a
conventional, gated, automatic reset circuit (not specifically
shown), which responds to each state change from 1 to 0 produced at
the output of timer 66 to reset only those devices not then
associated with an output block, such as block 52, then producing
an output signal. This arrangment positively places all such other
devices in conditions properly to respond to succeeding
transmissions.
5. Operational Description
Explaining now how system 10 and interpreter 48 therein perform,
let us assume initially that no transmitter in the system is
transmitting. Under such a condition, a 0 state exists on conductor
26, as well as on conductors 84, 90, 92, 96, 98, 108. The outputs
of gates 78, 80 place 0 states on conductors 100, 114,
respectively, and the output of gate 82 places a 1 state on
conductor 116. With respect to pulse counter 74, its nine output
terminals which are associated with counts 1-9, inclusive, are in 0
states, and this results in conductors 168b, 168c, 168a placing 0
states via conductors 162, 164, 166, respectively, on the lower
inputs of gates 170, 172, 174, respectively. The other output
terminal of counter 74 is in a 1 state. In counter 76, only that
output terminal associated with the count of "one" in the counter
is in a 1 state--the other two output terminals each being in a 0
state. Thus, conductor 184 applies a 1 state to the middle input of
gate 170, and conductors 186, 188 apply 0 states to the middle
inputs of gates 172, 174, respectively.
The 0 state on conductor 92 is applied to each of the upper inputs
of gates 170, 172, 174. The 0 state on conductor 114 is applied to
the clock input of flip-flop 128. And, the 1 state on conductor 116
is applied to the clock input of flip-flop 126.
The outputs of gates 170, 172, 174 are in 1 states, those of
circuits 178, 180, 182 are in 0 states, and that of gate 176 is in
a 1 state. The Q and D terminals of the flip-flops are all in 1
states. Consequently, the outputs of gates 130, 132 are each in a 0
state.
Considering what happens if a breakdown occurs in the sprinkler
system which is being monitored by transmitter 18, transmitter 18
is operated to produce in the telephone line a single round of
pulses, with the code 2-3-1. Such pulses, as they are produced on
conductor 26, are represented in Graph A in FIG. 4. It should be
appreciated that while each pulse shown in Graph A is represented
as a true square wave pulse, in actual practice such pulses might
have distinctly rounded corners, and other irregularities causing
them to deviate from true square waves.
The positive-going or leading edge of each pulse on conductor 26
causes input circuit 62 to generate a corresponding
controlled-duration follower pulse. Such follower pulses are shown
in Graph B in FIG. 4, and include pulses 190, 192, 194, 196, 198,
200 which are produced as the result of pulses 36, 38, 40, 42, 44,
46, respectively, shown in Graph A. The time alignments between
pulses in Graphs A and B are clearly apparent in FIG. 4. Each pulse
in Graph B has a closely controlled duration (shown at T.sub.4) of
about 0.05-seconds, as has been mentioned earlier.
One of the important advantages of employing circuit 62 to produce
such follower pulses, is that the duration-controlled follower
pulses serve to minimize the potential error-producing effects of
the time irregularities present in the actual pulses present on
conductor 26.
With initiation of pulse 190, timers 64, 66 are triggered,
whereupon they place 1 states on conductors 90, 98, respectively.
This situation is illustrated in Graphs C and F, respectively, in
FIG. 4 which show the voltage conditions in conductors 90, 98,
respectively. This state change on conductor 98 causes a 1 state to
be applied via conductors 104, 106, 112 to the upper inputs of
gates 80, 82, whereupon gate 82 places a 0 state on conductor 116.
This situation is illustrated in Graph H in FIG. 4 which depicts
the voltage condition on conductor 116. The output of gate 80
remains 0. No other change of consequence occurs at this time.
The negative-going or trailing edge of pulse 190 causes a state
change from 1 to 0 on the counting terminal of pulse counter 74,
which action results in counter 74 counting up to a count of "one."
As a consequence, a 1 state is applied through conductors 168a, 166
to the lower input of gate 174 in code latch circuit 122. However,
this state change produces no consequential effect.
Timers 64, 66 remain in conditions with 1 states on their outputs
until the occurrence of the next follower pulse, 192, because of
the fact that the time intervals between pulses 190, 192 is less
than the respective "time-out" times of these timers. More
specifically, the time interval between pulses 190, 192 is about
0.45-seconds. The time-out time of timer 64, shown at T.sub.5 in
Graph C, is about 0.6-seconds, and the time-out time of timer 66,
shown at T.sub.8 in Graph F, is about 1-second.
Initiation of pulse 192 retriggers timers 64, 66, and their outputs
remain in 1 states. The outputs of gates 80, 82 remain in 0 states.
The trailing edge of pulse 192 increases the count in counter 74 to
the count of "two." This change results in the lower input of gate
174 returning to a 0 state, and in the application via conductors
168b, 162 of a 1 state to the lower input of gate 170.
Because of the considerably larger time gap which exists between
pulses 38, 40 as compared with the gap between pulses 36, 38,
follower pulse 194, which is related to pulse 40, begins too late
in time to retrigger timer 64 soon enough to maintain the output
terminal of this timer in a 1 state. Referring to Graph B in FIG.
4, the time interval between pulses 192, 194 is about 0.7-seconds.
Thus, and as can be seen in Graph C, at about 0.6-seconds after the
end of pulse 192, timer 64 times out, and a state change from 1 to
0 occurs on its output and on conductor 90.
There thus results in Graph C a pulse 202 which serves to identify
and distinguish the completion of a single pulse section (section
I) in the round of pulses now being transmitted by transmitter 18.
The state change just mentioned which occurs at the trailing edge
of pulse 202 triggers read pulse generator 70, which then produces
a positive pulse shown at 204 in Graph D in FIG. 4. The duration of
this pulse, indicated by T.sub.6, is about 0.015-seconds.
Pulse 204 places a momentary 1 state on both conductors 92, 94. As
a consequence, there is a momentary situation where 1 states exist
simultaneously on all three of the inputs of gate 170. The 1 state
on the upper input of this gate results, of course, from the
momentary 1 state on conductor 92. The 1 state on the middle input
of the gate results from the 1 state initially applied, and still
applied, via conductor 184 from the output terminal of section
counter 76 associated with the count of "one" in this counter. The
1 state on the lower input of the gate results, as was previously
mentioned, from the fact that a count of "two" now exists in
counter 74.
The result of this situation is that a momentary 0 state is applied
by gate 170 to the set input of circuit 178, whereupon the output
of this circuit switches to and latches in a 1 state, which is
applied to the upper input of gate 176.
Thus, the circuitry just discussed in interpreter 48 has correctly
distinguished the first pulse section in the transmission from
transmitter 18, has read the number of pulses in this section,
which number is stored as the count of "two" in counter 74, has
compared this number of pulses with that for which the various
blocks, like block 52, have been programmed to respond to, and has
produced what might be thought of as a memorized response in block
52. It will be apparent that no such memorized response would have
occurred in block 52 had this block been programmed for a first
code number other than 2, or had the first-read pulse section
contained other than two pulses.
The trailing edge of pulse 204 triggers reset circuit 72, which
then produces a pulse such as that shown at 206 in Graph E in FIG.
4. Pulse 206 has a duration, indicated at T.sub.7, of about
0.015-seconds.
As a consequence, a momentary 1 state is applied to the upper input
of gate 78. The lower input of this gate is also now in a 1 state
because of the fact that code timer 66 is still in a condition
supplying a 1 state to conductor 98. The reason for this, of
course, is that the time interval between follower pulses 192, 194
(about 0.7-seconds) is less than the time-out time (about 1-second)
of timer 66. Thus, a momentary 1 state is applied to the output of
gate 78, and via conductors 100, 102 to the counting and reset
terminals, respectively, of counters 76, 74, respectively. Counter
74 is then reset to a zero-count condition, and counter 76 counts
up to a count of "two." This change in counter 76 results in a 0
state being placed on conductor 184, and a 1 state being placed on
conductor 186.
The various operations which then take place within the
interpreter, as the second and third sections of pulses in the
transmission from transmitter 18 are received, are similar to those
which have just been described. Thus, and referring to Graph C in
FIG. 4, timer 64 produces a pulse 208 which identifies and
distinguishes section II, and a later pulse 210 which identifies
and distinguishes section III. Throughout the production of these
other two pulses in Graph C, timer 66 continues to supply a 1 state
at its output, and gates 80, 82 continue to supply 0 states at
their outputs.
During receipt of the second section of the transmission, which
section contains pulses 40, 42, 44, pulse counter 74 counts up to a
count of "three," whereupon it places a 1 state via conductors
168c, 164 to the lower input of gate 172. As was previously
mentioned, because of the fact that section counter 76 now stores a
count of "two," a 1 state is applied via conductor 186 to the
middle input of gate 172. At the conclusion of pulse 208 in Graph
C, read pulse generator 70 is again triggered, this time to produce
a pulse 212 which is like pulse 204, and which places a momentary 1
state on the upper input of gate 172. Thereupon, circuit 180
latches into a condition supplying a 1 state to its output, and to
the middle input of gate 176. At the conclusion of pulse 212, reset
circuit 72 is again triggered, and produces a pulse 214 which is
like previously mentioned pulse 206. Pulse 214 results in the
application of a pulse from the output of gate 78 which resets
counter 74 to a zero-count condition, and places counter 76 in a
condition storing the count of "three."
Thus, the second section of pulses is identified, read, and
responded to in the code latch circuit. Similar action takes place
with respect to the third section containing pulse 46. Identifying
and reading of this third section ultimately results in circuit 182
latching in a condition applying a 1 state to its output terminal,
and to the lower input of gate 176. And, at this time, the output
of gate 176 switches from 1 to 0 which state change is sustained
and applied via conductors 140, 142 to the upper inputs of gates
130, 132. However, no change as yet occurs on the outputs of these
two gates.
The reset pulse which results following identification and reading
of pulse section III, resets counter 74 again to a zero-count
condition, and returns a count of "one" to counter 76. Thus,
counter 76 is returned to a proper condition for monitoring the
first pulse section of another round of pulses.
In the system operation which has just been described, it will be
recalled that transmitter 18 transmitted but a single coded round
of pulses. Therefore, follower pulse 200 was the last follower
pulse to be generated. Accordingly, about 1-second after the end of
this pulse, timer 66 times out, and returns a 0 state to its
output, and to conductor 98. This is clearly illustrated in Graph F
in FIG. 4. The state change from 1 to 0 which thus occurs on
conductor 98 is applied to the input of timer 68, to the lower
input of gate 78, and to the upper inputs of gates 80, 82.
With respect to gate 78, the return of a 0 state to its lower input
closes the gate, and, in effect, locks the output of the gate in a
0 state. This assures that counter 76 will remain in the condition
to which it has been returned (and which it had initially) storing
a count of "one." With respect to timer 68, the state change from 1
to 0 on the output of timer 66 triggers timer 68 into producing a
positive voltage pulse shown at 220 in Graph G in FIG. 4, which
pulse lasts about 0.75-seconds, indicated by T.sub.9. Thus, there
is now a 1 state applied from the output of timer 68 to the lower
inputs of gates 80, 82, and a 0 state applied to the upper inputs
of these gates. As a consequence, the ouput of gate 80 remains in a
0 state--the state which it has had all along--and the output of
gate 82 remains in a 0 state--the state to which it was initially
switched on initiation of follower pulse 190.
No further action of interest occurs until completion of pulse 220,
whereupon timer 68 returns a 0 state to its output terminal, which
state is then applied to the lower inputs of gates 80, 82. The
output of gate 80 remains in a 0 state. However, and as is
illustrated in Graph H, the output of gate 82 is switched from 0 to
1. Such switching results in clocking of device 126, with
consequent placement of a 0 state on its Q output. This 0 state is
applied via conductor 144 to the lower input of gate 130, and via
conductor 144 and conductor 146 to the D input of device 128.
A situation now exists with 0 states applies to both inputs of gate
130, whereupon the output of this gate switches from 0 to 1 and
applies a 1 state to conductor 152. Such switching is referred to
herein as an output signal from the interpreter of one type, which
output signal may be utilized in any suitable fashion to indicate
the information just transmitted by transmitter 18. The application
of a 0 state to the D input of device 128 inhibits this device from
producing any change on its Q output should anything effect
clocking of device 128. Such inhibiting is important in preventing
an improper output signal from now being produced through gate 132.
The output of gate 132 remains in a 0 state.
At the completion of such operation, and when the output signal
just produced has been noted, the manual reset circuits mentioned
earlier are operated to reset circuits 178, 180, 182, and devices
126, 128.
FIG. 5 illustrates what happens in the event of transmitter 18
operating to transmit a plurality of successive rounds of pulses,
as in the case of its reporting a fire. As can be seen from a
comparison of FIGS. 4 and 5, the operation within the interpreter
up through the beginning of pulse 220 is identical in both cases.
Immediately following the leading edge of pulse 220: gate 78 is
closed by virtue of there being a 0 state on its lower input; a 1
state is applied to the lower inputs of gates 80, 82, and a 0 state
to the upper inputs of these gates; and the outputs of gates 80, 82
are in 0 states. Conductors 140, 142 apply 0 states to the upper
inputs of gates 130, 132, and the Q outputs of devices 126, 128
apply 1 states to the lower inputs of gates 130, 132,
respectively.
Graph A in FIG. 5, at the right side thereof in the figure, shows
the beginning of the next successive round of coded pulses
transmitted by transmitter 18. More specifically, this graph shows
the beginning of a new section I in such a round, including pulses
222, 224. With transmittier 18 constructed as was previously
described, the nominal or expected time between successive rounds,
shown at T.sub.3 in graph A, is about 1-second. However, as can be
seen in Graph A, the actual time between the end of pulse 46 and
the beginning of pulse 222 is somewhat greater than this nominal
time.
For each of pulses 222, 224, circuit 62 produces a related follower
pulse, such being shown at 226, 228, respectively, in Graph B. It
is the leading edge of pulse 226 which is significant at this time.
This leading edge results in triggering of timer 66 to return a 1
state to its output. This is shown in Graph F. Such return of a 1
state results in the placement of 1 states on the upper inputs of
gates 80, 82. This change has no effect with respect to gate 82,
which continues to supply a 0 state at its output. However, in gate
80, its output is switched from 0 to 1, as indicated by Graph I in
FIG. 5.
This action, then results in clocking of device 128 to produce a 0
state on its Q output. As a consequence, a 0 state is applied both
to the lower input of gate 132, and to the D input of device 126.
Placement of such a state on the D input of device 126 inhibits any
change in the 1 state now existing at the Q output of device 126.
Placement of a 0 state on the lower input of gate 132 causes the
output of this gate to switch to a 1 state which is applied to
conductor 154. Such switching constitutes another type of output
signal from the interpreter, which may be utilized in any suitable
manner to indicate the specific information transmitted from
transmitter 18.
With noting of this output signal, manual resetting, as mentioned
above, is performed.
It will thus be apparent that the interpreter of the present
invention, through examining the major time differences which exist
between successive pulses transmitted in a system, accurately and
reliably discerns different groups or rounds of pulses, different
sections within rounds, and the code numbers associated with such
sections. For each different transmitter in a system it provides
two different discrete outputs for indicating, both, which specific
transmitter has transmitted, and what specific information it has
conveyed.
The interpreter immediately indicates whether a transmission from a
given transmitter comprises one round, or more than one round.
Human intervention is not required in the interpreting
operation.
While a preferred embodiment of the invention has been described
herein, it is appreciated that variations and modifications may be
made without departing from the spirit of the invention.
* * * * *