U.S. patent number 3,864,518 [Application Number 05/368,265] was granted by the patent office on 1975-02-04 for signal conversion apparatus.
Invention is credited to Meguer V. Kalfaian.
United States Patent |
3,864,518 |
Kalfaian |
February 4, 1975 |
Signal conversion apparatus
Abstract
Identification of complex signals such as a specific phoneme
spoken by different speakers is accomplished by analyzing and
normalizing the spoken phoneme's group of frequencies (formants) to
a standard group, while maintaining the original harmonic-ratio
information as channel number differences. A set of filters
followed by rectifiers, to an electronic switching matrix, shifts
the original filter output set through sequential sets of channels
until the fundamental frequency at some input channel activates the
lowest numbered ouput channel.
Inventors: |
Kalfaian; Meguer V. (Los
Angeles, CA) |
Family
ID: |
26929332 |
Appl.
No.: |
05/368,265 |
Filed: |
June 8, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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235943 |
Mar 20, 1972 |
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Current U.S.
Class: |
704/254 |
Current CPC
Class: |
G10L
15/00 (20130101) |
Current International
Class: |
G10L
15/00 (20060101); G10l 001/00 () |
Field of
Search: |
;179/1SA,1SB,15.55R,15.55T |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Claffy; Kathleen H.
Assistant Examiner: Kemeny; E. S.
Parent Case Text
This is a continuation of application Ser. No. 235,943, filed Mar.
20, 1972 .
Claims
What I claim, is:
1. The system normalizing spectral variations of a group of
information-bearing harmonically related frequency peak resonances
in a complex sound wave by converting and standardizing the
channel-location identities of said resonances, the system
comprising a plurality of band-pass filters for separating the
resonances of said complex wave in divisions such that the center
frequency of said filters are arranged in a monotonically
increasing series of frequencies; said series comprising a
plurality of sub-series, all sub-series having the same number of
channels such that each frequency in a sub-series is harmonically
related to the same-placed frequency in the other sub-series; said
filters being numbered sequentially for identity from the reference
numeral one; a plurality of detectors for derivng detected signals
from said band-pass filters, said detectors having numerical
identities the same as the associated filters; a signal conversion
switching arrangement comprising a plurality of input and output
channels numbered sequentially, said switching comprising a
plurality of AND-gates numerically identified from a reference
numeral; first parallel connections of the first inputs of the
corresponding AND-gates to corresponding input channels, second
inputs of corresponding AND-gates to corresponding
channel-switching control-gate inputs, third parallel connections
of the outputs of corresponding AND-gates to corresponding output
channels; coupling means from said detectors to corresponding first
inputs of AND-gates; means for energizing said parallel-connected
second inputs sequentially for said signal-switching conversion,
all input channels being switched simultaneously to sequentially
lower-number channels, until said group of detected signals are
admitted to the output channels in an order such that the detected
signal having the lowest numerical identity within the input group
of signals is switched to the output channel having said reference
numeral one, while the other detected signals of the input group
are switched to corresponding output channels, such that the
information concerning input frequency harmonic ratios is
maintained relative to the input fundamental frequency, and thereby
having input channels to a normalized group of output channels.
2. Apparatus in the system as set forth in claim 1, wherein said
plurality of AND-gates in each of said channels consist of
semiconductor devices, each device having first and second
electrodes for forming electrical conductive path therebetween, and
a third electrode for controlling the resistance of said conductive
path, and said devices are assembled in numerically identified
plurality of rows in linear numerical successions from a reference
numeral, in each of said rows said devices being identified
numerically in linear numerical successions from said reference
numeral, and said devices being numerically aligned in the
assembly; first parallel connections of the first electrodes of the
numerically corresponding devices in said parallel rows,
respectively, for forming said first inputs of said channels;
second parallel connections of the third electrodes of the
numerically identified devices in the numerically succeeding rows
with that of the third electrodes of the numerically succeeding
devices from the numerically corresponding devices in the
numerically preceding rows, respectively, for forming said second
inputs of said channels; and third parallel connections of the
second electrodes of the numerically identified devices in said
rows, respectively, for forming said channel outputs.
Description
This invention involves the identification of complex signals such
as a specific phoneme spoken by different speakers. The basic
problem, for example, may be that of recognizing a phoneme spoken
in a low-pitched voice, and the same phoneme in a higher-pitched
voice. It is well-known that a specific phoneme is a complex wave
consisting of harmonically related frequency peaks, or resonances.
Thus, it is well known that normalizing any arbitrarily pitched
phoneme to a standard pitch set of harmonic frequencies
representing the phoneme may simplify the recognition process. Such
normalizing to a standard configuration may be accomplished by
various forms of signal conversion systems.
This invention relates to signal conversion systems, and more
particularly to a novel filter plus switching arrangement for
regrouping (shifting) randomly originated complex signals to a
reference grouping for simpler processing in a recognition device,
for example, speech sound waves, voice print waves, sonar target
waves, and so on.
Thus the particular arrangement disclosed herein is contemplated as
being sufficiently versatile for a wide scope of uses, as will be
apparent from the following specification in conjunction with the
accompanying drawings, wherein:
FIG. 1 is a partly block and partly schematic diagram of the
invention;
FIG. 2 shows the special center frequency sub-divisions of the
pass-band filters, as used in the present invention;
FIG. 3 is a numerical chart showing how the detected signal outputs
of the pass-band filters are switched linerarly to the outputs of
the numerically arranged channels in accordance with the present
invention; and
FIG. 4 shows how a plurality of and-gates (analog switches) can be
physically oriented on a planar surface for simple interconnections
of terminals for the required switching arrangement.
In order to obtain high accuracy of signal regrouping without
causing any cross switching of the input signal to the channel
outputs, the center frequencies of the sub-dividing pass-band
filters are arranged as in FIG. 2, wherein the sub-divisions are
similar to the standard musical scale. In this arrangement, it will
be noted that the sub-divisions are arranged in a series of
digitals at like intervals in harmonic successions corresponding to
the digitals in preceding intervals. Thus, the numerical ratios of
the numerals from the second through the thirteenth numerals with
respect to the first numeral is the same as the numerical ratios of
the fourteenth through the twentififth numeral with respect to the
thirteenth numeral, as exemplary demonstration. Such a numerical
arrangement simplifies the actual channel switching arrangement,
because it requires linearly sequenced numerical transfer without
cross coupling of any of the pass-band outputs, such as would be by
the arrangement of pass-band center frequencies of the filters
shown in FIG. 11, and the chart of switching combinations in FIG.
12 of my related U.S. Pat. No. 3,622,706 issued Nov. 23, 1971. This
is shown in greater clarity by the numerical chart in FIG. 3,
wherein the top row of the numerals represent the channels, and the
rows of numerals below represent the sequence of the numerals left
hand of the sub-band frequencies in FIG. 2. For example, in the
first row (FIG. 3), all of the detected outputs of pass-band
filters (starting from filter number-1) are applied to the inputs
of the channels starting from channel number-1. In the second row,
the detected filter outputs starting from the number-2 filter are
applied to all of the channels starting from the channel number-1,
and so on. As stated in the foregoing, such simplicity of switching
sequence becomes inherently accurate, as long as the harmonic
sequence at like intervals is considered in sub-dividing the sound
spectrum, because the number of sub-band divisions and center
frequencies of the pass-band filters may be arranged other than the
frequencies shown in FIG. 2 without affecting the required
accuracy.
Switching apparatus of FIG. 4
In reference to the chart shown in FIG. 3, it is apparent that the
use of a large number of switching transistors is required for the
switching performance. While multiple element channel swiches in
small packages of integrated circuits are available, it still will
require large surface of printed circuit board with a large number
of terminals to be soldered. Due to the simplicity of
interconnecting design, however, a large number of these
transistors, or any type of controllable semiconductors, may be
integrated on a single wafer, such as shown in FIG. 4, wherein,
each square represents the semiconductor as mentioned, three
squares of which are shown in shaded lines in order to render them
distinguishable in the maze of electrical connections. The
connecting electrodes in each square are represented by the black
dots to which are terminated the required parallel connections, as
illustrated by the horizontal, vertical, and 45.degree. parallel
lines; the first representing the source electrode terminals, the
second representing the drain terminals, and the third representing
the gate electrode terminals of MOS FET transistors, although other
types may also be used. Similarly, if enormously large number of
transistors are to be deposited on a single wafer, it may be
preferable to divide the arrangement of FIG. 4 into segments, in
flat packages with connecting terminals attached thereto, so that
the terminals of these segments may be connected externally for the
complete assembly, as required.
Having described the details of parts for signal conversion of
complex groups of signals, an exemplary system for signal
conversion is shown in FIG. 1.
Signal conversion system of FIG. 1
I have described novel signal conversion systems in my related
patents, for example, U.S. Pat. No. 3,622,706, U.S. Pat. No.
3,659,051, and copending applications Ser. Nos. 97,893 and 209,661,
and reference may be made to these disclosures. However a simpler
arrangement, in an exemplary form, may be described by way of the
arrangement in FIG. 1, wherein the voice signals in block 1 are
applied to the pass-band filters in blocks 2 through 5, for
sub-dividing the sound spectrum band in the sequence of resonances,
as shown in FIG. 2. The outputs of these pass-band filters are
first detected in the blocks 6 through 9, respectively, and applied
to the drain electrodes of switching transistors Q1 through Q4
(these switching transistors may also be termed as and-gates for
the purpose contemplated herein, and therefore, the same
terminology will also be used in the appended claims),
respectively. The source electrodes of these transistors are
connected to ground in series with the output resistors R1, R2, R3,
and Rn, which represent the channel outputs for signal conversion
of the arriving signals from the detected signals in blocks 6
through 9. In accordance with the numerical chart of FIG. 3, any
one of the detected signals in blocks 6 through 9 may be coupled to
the resistor R1 of channel-1. This is done by the additional
transistors Q5, Q8, Q10, the source electrodes of which are all
connected in parallel with the source electrode of Q1. Thus, when
the first distributor pulse from the pulse distributor in block 10
is applied to the gate electrode of Q1 the detected signal of block
6 is admitted to the output resistor R1. When the second
distributor pulse is applied to the gate electrode of Q5 the
detected signal from block 7 is admitted to the output resistor R1.
By such sequential pulse distribution to the gate electrodes of Q1,
Q5, Q8, Q10, it is seen that any one of the detected outputs of the
pass-band filters may be admitted to the resistor R1 of the
channel-1. By such example, similar signal transfers are made to
the channel outputs across resistors R2, R3, and Rn, in the linear
numerical order of the chart in FIG. 3, by the parallel connections
of the gate electrodes of transistors Q1 through Q4; Q5 through Q7;
and Q8-Q9, etc., as shown in the drawing. Thus, as the distributor
in block 10 applies sequential pulses to the parallel connected
gate electrodes, as shown, the detected signals in blocks 6 to 9
are sequentially transferred to the channel outputs in the signal
regrouping combinations of the chart in FIG. 3. During this
sequence, one of the signal regrouping combinations at the channel
outputs may represent the desired information, which may be
decoded, or used, for any particular purpose that may be
desired.
While the arrangement of FIG. 1 is given in an exemplary form,
showing how signal conversion may be accomplished by the novel
transistor arrangements of FIGS. 1 and 4, reference may be made to
my disclosures in my reference patents for greater details of these
signal conversion systems, because the gating functions of these
transistors in the arrangement of FIG. 1 and FIG. 4 is contemplated
for a wide scope of uses, and accordingly, both the arrangements
and specific parts that I have mentioned in exemplary form may vary
without departing from the true spirit and scope of the invention
.
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