US3668322A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dynamic presence equalizer
Assignee: CBS Broadcasting Inc
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Filing: 1970-06-18
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Granted: 1972-06-06
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Expires: 1990-06-18
Abstract
Abstract A speech processing device operative to correct deficiencies in speech programs caused by inadequate energy in the ''''presence band.'''' The device determines the relative amount of total signal energy in the presence band, and, if it is inadequate, automatically boosts the amplitude of presence band components to a level to obtain a more optimum spectral distribution. The circuit is designed to operate with an automatic speech-music discriminator which inhibits control action during music programming.
Inventors
- 👤 Richard G Allen
- 👤 Emil Torick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:58
CPC Classifications
H; H03; H03G; H03G5/00; H03G5/16; H03G5/18; H03G5/22
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
194 words
An audio frequency signal processing system for improving the quality of audio frequency signals, comprising, a signal input circuit for receiving input audio frequency signals, first circuit means having an input terminal connected to said input circuit, a control terminal, and an output terminal, said first circuit means being normally operative to substantially uniformly amplify all frequency components of said input signal over the audio frequency range and to provide in response to application of a control signal greater amplification of frequency components of said input signal appearing in the frequency band between about 2,000 Hz and about 4,000 Hz in proportion to the degree that the level of energy in said 2,000 Hz to 4,000 Hz band components is less than the total energy in said input signal, and control circuit means connected between the output terminal and the control terminal of said first circuit means operative continuously to compare the energy content of the signal at the output terminal with the energy content of the frequency components in said 2,000 Hz to 4,000 Hz band and to apply to said control terminal a control signal having a magnitude proportional to the difference.
Claim 2
Dependent Claim
194 words
An audio frequency signal processing system for improving the quality of audio frequency signals, comprising, a signal input circuit for receiving input audio frequency signals, first circuit means having an input terminal connected to said input circuit, a control terminal, and an output terminal, said first circuit means being normally operative to substantially uniformly amplify all frequency components of said input signal over the audio frequency range and to provide in response to application of a control signal greater amplification of frequency components of said input signal appearing in the frequency band between about 2,000 Hz and about 4,000 Hz in proportion to the degree that the level of energy in said 2,000 Hz to 4,000 Hz band components is less than the total energy in said input signal, and control circuit means connected between the output terminal and the control terminal of said first circuit means operative continuously to compare the energy content of the signal at the output terminal with the energy content of the frequency components in said 2,000 Hz to 4,000 Hz band and to apply to said control terminal a control signal having a magnitude proportional to the difference.
Claim 3
Dependent Claim
94 words
A system according to claim 1 wherein said control circuit means includes first and second rectifiers operative to produce first and second direct current signals having amplitudes proportional to the energy content of said signal at the output terminal and to the energy content of the frequency components in said 2,000 Hz to 4,000 Hz band, respectively, and means for combining said first and second direct current signals to produce a control signal having a magnitude inversely proportional to the amount of 2,000 Hz to 4,000 Hz band energy in the total input signal.
Claim 4
Dependent Claim
41 words
A system according to claim 2 wherein said combining means comprises an analog divider circuit to which said first and second signals are applied and operative to produce a control signal proportional to the quotient of said first and second signals.
Claim 5
Dependent Claim
29 words
A system according to claim 2 wherein said input circuit includes means for controlling the level of said input signals, and wherein said combining means is a differential amplifier.
Claim 6
Dependent Claim
82 words
A system according to claim 1 wherein said control circuit means further includes a gate circuit through which said control signal is applied to said control terminal, and second circuit means interconnected between the output terminal of said first circuit means and said gate circuit operative in response to the presence of music in said input signal to deliver an inhibit signal to said gate circuit to prevent application of said control signal to the control terminal of said first circuit means.
Claim 7
Dependent Claim
46 words
A system according to claim 5 wherein said second circuit means comprises a speech-music discriminator operative to produce an inhibit signal in response to the presence of music in said input signal whereby said first circuit means provides substantially uniforM amplification of input signals containing music.
Claim 8
Dependent Claim
139 words
A system according to claim 1 wherein said first circuit means includes an amplifier having first and second input terminals, and circuit means for applying said input signals to said first and second input terminals in push-pull relationship, said circuit means including respective first and second substantially resistive signal paths and respective third and fourth circuit paths in parallel with said first and second resistive paths, respectively, and having a parallel resonant circuit connected between said third and fourth paths resonant at the center of said 2,000 Hz to 4,000 Hz band, said third and fourth circuit means further including control means to which said control signal is applied and operative in response to an increase in the magnitude of said control signal to increase the proportion of said input signal carried by said third and fourth circuit paths.
Claim 9
Dependent Claim
42 words
A system according to claim 7 wherein said control means includes first and second light dependent resistors connected in said third and fourth circuit paths, respectively, and a lamp positioned to illuminate said light dependent resistors and energized by said control signal.
Claim 10
Dependent Claim
50 words
A system according to claim 1 wherein said first circuit means has a substantially flat amplification vs. frequency characteristic over the frequency range of interest in the absence of control signal, and approximates an inverted 70 phon equal loudness contour, peaked at approximately 3.5 KHz, when control signal is present.
Claim 11
Dependent Claim
17 words
A system according to claim 7 wherein said parallel resonant circuit is resonant at approximately 3.5 KHz.
Claim 12
Dependent Claim
46 words
A system according to claim 2 wherein said first circuit means has a substantially flat amplification vs. frequency characteristic over the frequency range of interest in the absence of control signal, and approximates an inverted 70 phon equal loudness contour when maximum control signal is present.
Claim 13
Dependent Claim
127 words
A system according to claim 2 wherein said control circuit means further includes a gate circuit through which said control signal is applied to said control terminal, a speech-music discriminator connected between the output terminal of said first circuit means and said gate circuit operative in response to the presence of music in said input signal to deliver an inhibit signal to said gate circuit to prevent application of said control signal to the control terminal of said first circuit means, and wherein said first circuit means has a substantially flat amplification vs. frequency characteristic over the frequency range of interest in the absence of control signal, and approximates an inverted 70 phon equal loudness contour, peaked at approximately 3.5 KHz, when maximum control signal is present.
Claim 14
Dependent Claim
132 words
A system according to claim 12 wherein said first circuit means includes an amplifier having first and second input terminals, and circuit means for applying said input signal to said first and second input terminals in push-pull relationship, said circuit means including respective first and second substantially resistive signal paths, and respective third and fourth circuit paths in parallel with said first and second resistive paths, respectively, and having a parallel resonant circuit connected between said third and fourth paths resonant at approximately 3.5 KHz, said third and fourth circuit paths further including control means to which said control signal is applied and operative in response to an increase in the magnitude of said control signal to increase the proportion of said input signal carried by said third and fourth circuit paths.
Claim 15
Dependent Claim
43 words
A system according to claim 13 wherein said control means includes first and second light dependent resistors connected in said third and fourth circuit paths, respectively, and an incandescent lamp positioned to illuminate said light dependent resistors and energized by said control signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |