US4359604A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for the detection of voice signals
Assignee: Thales SA
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Filing: 1980-09-25
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Granted: 1982-11-16
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Expires: 2000-09-25
Abstract
Abstract A detection apparatus for receiving an input signal containing noise and for detecting the presence of voice signals therein comprises means for attenuating the input signal and a comparator of the amplitude of the attenuated input signal relative to a variable threshold voltage. This threshold voltage is generated by control means which make the threshold voltage dependent on the peak amplitude value of the input signal. A control signal corresponding to the detection of voice signals is supplied by decision means which carry out a time analysis of the output signal of the comparator.
Inventors
- 👤 Francois Dumont
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:45
CPC Classifications
G; G10; G10L; G10L25/00; G10L25/78; H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/32
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
274 words
A detection apparatus for receiving an input signal containing noise and for detecting therein the presence of voice signals comprising: a threshold voltage generator having a control input and an output for supplying a threshold voltage which either rises exponentially as a function of time in accordance with a first time constant which exceeds a maximum syllable period, or drops exponentially in accordance with a second time constant which exceeds the maximum pitch period; control means having a first and a second input for respectively receiving the input signal and the threshold voltage and an output coupled to the control input of the generator for supplying a control signal making the threshold voltage rise as long as the input signal peak amplitude is greater than the threshold voltage, and making it drop in the opposite case; attenuation means in a ratio k (k being equal to a positive integer which is not zero) for receiving the input signal and having an output for supplying an attenuated signal; comparison means for comparing the amplitude of the attenuated signal with the threshold voltage and having an output for supplying a first intermediate signal when the amplitude of the attenuated signal exceeds the threshold voltage; decision means coupled to the output of the comparison means for supplying a signal corresponding to a detection of voice signal when the first intermediate signal shows a burst of transitions whose total duration is greater than T S (the lower bound of the syllabic period) and when each two successive transitions in the same direction is separated by a time interval lower than Tn (the upper bound of the pitch period).
Claim 2
Dependent Claim
274 words
A detection apparatus for receiving an input signal containing noise and for detecting therein the presence of voice signals comprising: a threshold voltage generator having a control input and an output for supplying a threshold voltage which either rises exponentially as a function of time in accordance with a first time constant which exceeds a maximum syllable period, or drops exponentially in accordance with a second time constant which exceeds the maximum pitch period; control means having a first and a second input for respectively receiving the input signal and the threshold voltage and an output coupled to the control input of the generator for supplying a control signal making the threshold voltage rise as long as the input signal peak amplitude is greater than the threshold voltage, and making it drop in the opposite case; attenuation means in a ratio k (k being equal to a positive integer which is not zero) for receiving the input signal and having an output for supplying an attenuated signal; comparison means for comparing the amplitude of the attenuated signal with the threshold voltage and having an output for supplying a first intermediate signal when the amplitude of the attenuated signal exceeds the threshold voltage; decision means coupled to the output of the comparison means for supplying a signal corresponding to a detection of voice signal when the first intermediate signal shows a burst of transitions whose total duration is greater than T S (the lower bound of the syllabic period) and when each two successive transitions in the same direction is separated by a time interval lower than Tn (the upper bound of the pitch period).
Claim 3
Dependent Claim
91 words
A detection apparatus according to claim 1, wherein the decision means comprises a first timing device having an input coupled to the output of the comparison means and an output for supplying a second intermediate signal corresponding to the first intermediate signal extended by a duration equal to Tm, and a second timing device having an input coupled to the output of the first timing device and an output being the output of the decision means and supplying a signal when the duration of the first signal exceeds T S .
Claim 4
Dependent Claim
96 words
A detection apparatus according to claim 2, wherein the control means comprises a comparator having a first input receiving the input signal and a second input receiving the threshold voltage supplied by the generator and an output for supplying an intermediate control signal when the input signal peak amplitude exceeds the threshold voltage, and a timing device having an input coupled to the comparator output and an output coupled to the output fo the control means for supplying a control signal which is the intermediate control signal extended by a duration equal or greater than Tm.
Claim 5
Dependent Claim
73 words
A detection apparatus according to claim 2, wherein the voltage generator comprises a switch having a control input being the control input of the generator, a voltage supply, a first resistor, a second resistor, a capacitor having a first end coupled to earth and a second end coupled either to earth across the first resistor or to the voltage supply across the second resistor, said second end constituting the output of the generator.
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) | 1985-11-15 | 1986-05-17 | 1986-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-15 | 1990-05-17 | 1990-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-15 | 1994-05-17 | 1994-11-16 | $7700.00 | Window Closed / Lapsed |