CA1160574A - Device for the processing of voice signals - Google Patents
Device for the processing of voice signalsInfo
- Publication number
- CA1160574A CA1160574A CA000336629A CA336629A CA1160574A CA 1160574 A CA1160574 A CA 1160574A CA 000336629 A CA000336629 A CA 000336629A CA 336629 A CA336629 A CA 336629A CA 1160574 A CA1160574 A CA 1160574A
- Authority
- CA
- Canada
- Prior art keywords
- signals
- delay line
- source
- input signals
- voice
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/34—Muting amplifier when no signal is present or when only weak signals are present, or caused by the presence of noise signals, e.g. squelch systems
- H03G3/345—Muting during a short period of time when noise pulses are detected, i.e. blanking
Abstract
ABSTRACT OF THE DISCLOSURE
A processing device transmits speech signals of constant amplitude during periods of voice activity and interrupts transmission outside these periods, so that noise is not transmitted.
to this end the processing device comprises an amplitude-compressing device preceeded by a voice activity detector constituted by a delay line in series with an electronic switch and a speech - noise discriminator having a common input with the delay line for receiving the voice signals. The switch is controlled by the output signal of the discriminator in such a way that it only permits the passage of the voice signals corresponding to the periods of voice activity.
A processing device transmits speech signals of constant amplitude during periods of voice activity and interrupts transmission outside these periods, so that noise is not transmitted.
to this end the processing device comprises an amplitude-compressing device preceeded by a voice activity detector constituted by a delay line in series with an electronic switch and a speech - noise discriminator having a common input with the delay line for receiving the voice signals. The switch is controlled by the output signal of the discriminator in such a way that it only permits the passage of the voice signals corresponding to the periods of voice activity.
Description
:~ACKGROUND OF THh INVENTION
~l~he present invention relates to devices for processing voice signals from a transmitter having means for com-pressing their amplitude.
During the standard transmission of a speech signal the ratio between the peak power and the average power of the words is of the order of 15 dB, so that there is a poor transmission balance. ~o obviate this it is known to use devices for compressing the amplitude of the trans-mitted speech signal.
All the devices used (compression loop, saturatedamplifier, etc.) strongly amplify the noise during the periods o~ silence of the transmitted speech, which makes reception very unpleasant.
BRIEF SUM~RY OF THE INVENTION
The problem of the invention is to obviate this disadvantage.
According to the invention this problem is solved by a voice signal transmitting device having an amplitude compression device for supplying amplitude-compressed signals and means for detecting voice activity in order to interrupt the supply of compressed signals when voice activity is present.
DE~CXIPq~ION OF THE DXAWING AND :I?REFERRED EMBODIMEN~S
~he invention is described in greater detail herein-after relative to a non-limitative embodiment and with reference to the attached drawing.
The drawing shows an input terminal 10 receiving a voice signal and which is connected in parallel to '' $~' 1~S74 the input of a delay line 1 and to the input of a speech-noise discriminator 2. At its input an electronic switch 3 receives the output signal from the delay line 1 and is controlled by the output signal of discriminator
~l~he present invention relates to devices for processing voice signals from a transmitter having means for com-pressing their amplitude.
During the standard transmission of a speech signal the ratio between the peak power and the average power of the words is of the order of 15 dB, so that there is a poor transmission balance. ~o obviate this it is known to use devices for compressing the amplitude of the trans-mitted speech signal.
All the devices used (compression loop, saturatedamplifier, etc.) strongly amplify the noise during the periods o~ silence of the transmitted speech, which makes reception very unpleasant.
BRIEF SUM~RY OF THE INVENTION
The problem of the invention is to obviate this disadvantage.
According to the invention this problem is solved by a voice signal transmitting device having an amplitude compression device for supplying amplitude-compressed signals and means for detecting voice activity in order to interrupt the supply of compressed signals when voice activity is present.
DE~CXIPq~ION OF THE DXAWING AND :I?REFERRED EMBODIMEN~S
~he invention is described in greater detail herein-after relative to a non-limitative embodiment and with reference to the attached drawing.
The drawing shows an input terminal 10 receiving a voice signal and which is connected in parallel to '' $~' 1~S74 the input of a delay line 1 and to the input of a speech-noise discriminator 2. At its input an electronic switch 3 receives the output signal from the delay line 1 and is controlled by the output signal of discriminator
2. Delay line 1, discriminator 2 and electronic switch
3 constitute a voice activity detector. This electronic switch 3 is connected to the output terminal 11 of the voice signal processing device across an amplitude compressing device 4.
The device functions in the following manner.
q'he speech - noise discriminator 2 supplies at its outpu-t a signal which switches off the electronic switch 3, when the input signal received on terminal 10 is a speech signal. However, as the control of electronic switch 3 takes place with a time lag T1 (time necessary for the processing of its control signal) compared with the input signal (received on terminal 10) the delay line 1 must have a delay equal to ~1' so that electronic switch 3 is only switched off when a speech signal appears at its input. ~he output signal of electronic switch 3 is then amplified and compressed by the amplitude compressing device 4 which will then supply a speech signal of constant amplitude to output terminal 11.
~his device supplies speech signals of constant amplitude during the period of vocal activity, but supplies no signal (except for the noise of this amplitude compressor) outside these periods.
~he invention is not limited to the embodiment des-cribed and represented hereinbefore and in particul~r 1160~74 the device can be constructed in accordance with the following variantsO
~he compressing device 4 can either be a compression loop with a rapid resensitizing constant, whereby the signals are amplified up to a predetermined peak value imposed by the compression loop, or the saturated amplifier.
The speech compression device 4 can advantageously be inserted in series between the delay line 1 and the electronic switch 3, making it possible to eliminate the noise of said device outside the voice activity periods.
Such devices can be in particular used in transmitters transmittin~ speech signals.
The device functions in the following manner.
q'he speech - noise discriminator 2 supplies at its outpu-t a signal which switches off the electronic switch 3, when the input signal received on terminal 10 is a speech signal. However, as the control of electronic switch 3 takes place with a time lag T1 (time necessary for the processing of its control signal) compared with the input signal (received on terminal 10) the delay line 1 must have a delay equal to ~1' so that electronic switch 3 is only switched off when a speech signal appears at its input. ~he output signal of electronic switch 3 is then amplified and compressed by the amplitude compressing device 4 which will then supply a speech signal of constant amplitude to output terminal 11.
~his device supplies speech signals of constant amplitude during the period of vocal activity, but supplies no signal (except for the noise of this amplitude compressor) outside these periods.
~he invention is not limited to the embodiment des-cribed and represented hereinbefore and in particul~r 1160~74 the device can be constructed in accordance with the following variantsO
~he compressing device 4 can either be a compression loop with a rapid resensitizing constant, whereby the signals are amplified up to a predetermined peak value imposed by the compression loop, or the saturated amplifier.
The speech compression device 4 can advantageously be inserted in series between the delay line 1 and the electronic switch 3, making it possible to eliminate the noise of said device outside the voice activity periods.
Such devices can be in particular used in transmitters transmittin~ speech signals.
Claims (3)
1. Apparatus for processing input signals which comprise voice signals and, during periods of voi-ce inactivity, unwanted noise signals, said apparatus functioning to remove substantially all of said noise signals and comprising:
(a) means, connected to the source of said input signals, for generating a control signal only when said input signals comprise voice signals;
(b) switching means, connected between the source of said input signals and the output of the appa-ratus and controlled by said control signal, for closing a path between said source and said output;
(e) a delay line interposed between the source of said input signals and the input to said switching means, said delay line having a delay T, substantially equal to the response time of said control signal gene-rating means; and (d) an amplitude compression device in the path between the source of said input signals and said output, downstream of said delay line.
(a) means, connected to the source of said input signals, for generating a control signal only when said input signals comprise voice signals;
(b) switching means, connected between the source of said input signals and the output of the appa-ratus and controlled by said control signal, for closing a path between said source and said output;
(e) a delay line interposed between the source of said input signals and the input to said switching means, said delay line having a delay T, substantially equal to the response time of said control signal gene-rating means; and (d) an amplitude compression device in the path between the source of said input signals and said output, downstream of said delay line.
2. The apparatus according to claim 1, wherein said amplitude compression device is also downstream of said switching means.
3. The apparatus according to claim 1, wherein said amplitude compression device is upstream of said switching means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7827922 | 1978-09-29 | ||
| FR7827922A FR2437744A1 (en) | 1978-09-29 | 1978-09-29 | DEVICE FOR PROCESSING VOICE MODULATION SIGNALS AND TRANSMITTER COMPRISING SUCH A DEVICE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1160574A true CA1160574A (en) | 1984-01-17 |
Family
ID=9213184
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000336629A Expired CA1160574A (en) | 1978-09-29 | 1979-09-28 | Device for the processing of voice signals |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4286116A (en) |
| EP (1) | EP0010022A1 (en) |
| JP (1) | JPS5548799A (en) |
| AR (1) | AR219824A1 (en) |
| AU (1) | AU5106379A (en) |
| BR (1) | BR7906214A (en) |
| CA (1) | CA1160574A (en) |
| FR (1) | FR2437744A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL84948A0 (en) * | 1987-12-25 | 1988-06-30 | D S P Group Israel Ltd | Noise reduction system |
| US5220610A (en) * | 1990-05-28 | 1993-06-15 | Matsushita Electric Industrial Co., Ltd. | Speech signal processing apparatus for extracting a speech signal from a noisy speech signal |
| JPH07281689A (en) * | 1994-04-08 | 1995-10-27 | Matsushita Electric Ind Co Ltd | Audio signal transmission device |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3126449A (en) * | 1964-03-24 | Shirman | ||
| GB1427029A (en) * | 1972-12-14 | 1976-03-03 | Cunard Steam Ship | Radio receiving apparatus |
| US3872250A (en) * | 1973-02-28 | 1975-03-18 | David C Coulter | Method and system for speech compression |
| US3902123A (en) * | 1973-11-30 | 1975-08-26 | Cincinnati Electronics Corp | Digital circuit for determining if signal source consists primarily of noise or contains information |
| US3947636A (en) * | 1974-08-12 | 1976-03-30 | Edgar Albert D | Transient noise filter employing crosscorrelation to detect noise and autocorrelation to replace the noisey segment |
| US3952158A (en) * | 1974-08-26 | 1976-04-20 | Kyle Gordon L | Ear protection and hearing device |
| DE2601940A1 (en) * | 1976-01-20 | 1977-07-21 | Ulrich Kraus | Gain controlled amplifier for audio systems - delays input so that gain change takes place before input arrives |
| US4071695A (en) * | 1976-08-12 | 1978-01-31 | Bell Telephone Laboratories, Incorporated | Speech signal amplitude equalizer |
| US4143325A (en) * | 1976-08-20 | 1979-03-06 | Kahn Leonard R | Constant amplitude interference squelch system |
| US4143333A (en) * | 1977-05-16 | 1979-03-06 | David P. Misunas | Impulse noise removing apparatus |
-
1978
- 1978-09-29 FR FR7827922A patent/FR2437744A1/en active Granted
-
1979
- 1979-09-18 EP EP79400655A patent/EP0010022A1/en not_active Withdrawn
- 1979-09-21 AU AU51063/79A patent/AU5106379A/en not_active Abandoned
- 1979-09-25 US US06/078,805 patent/US4286116A/en not_active Expired - Lifetime
- 1979-09-27 BR BR7906214A patent/BR7906214A/en unknown
- 1979-09-28 CA CA000336629A patent/CA1160574A/en not_active Expired
- 1979-09-28 JP JP12524379A patent/JPS5548799A/en active Pending
- 1979-09-28 AR AR278253A patent/AR219824A1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| EP0010022A1 (en) | 1980-04-16 |
| JPS5548799A (en) | 1980-04-08 |
| FR2437744A1 (en) | 1980-04-25 |
| AR219824A1 (en) | 1980-09-15 |
| BR7906214A (en) | 1980-07-15 |
| AU5106379A (en) | 1981-04-02 |
| US4286116A (en) | 1981-08-25 |
| FR2437744B1 (en) | 1981-08-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| GB1387074A (en) | Loudspeaking telephone sets | |
| MY115592A (en) | Method and apparatus for controlling a telephone ring signal | |
| NO990982D0 (en) | Microphone mute in telecommunication systems | |
| GB2380341B (en) | Automatic gain control circuit and an RF receiver and method using such a circuit | |
| TW338871B (en) | Pre-emphasis network with variable time delay | |
| CA1160574A (en) | Device for the processing of voice signals | |
| US6070088A (en) | Mobile telephone set with automatic sound level control | |
| AU554265B2 (en) | Tone receiver in digital data communication system | |
| CA1108236A (en) | Level control circuitry for two way communication system | |
| US5912923A (en) | System for transmitting coded speech signals | |
| JPS6473831A (en) | Bidirectional catv system | |
| JPS57170640A (en) | Receiver having self-diagnosing function | |
| JPS57135600A (en) | Listening device | |
| ES2017867A6 (en) | Call receiver for radio-communication services | |
| JPS57104312A (en) | Control device for sound volume of acoustic device | |
| JPS57159158A (en) | Audio switch circuit | |
| JPS57100362A (en) | Ultrasonic wave measuring device | |
| JPS5644252A (en) | Incoming frequency speaking unit | |
| JPS5734469A (en) | Automatic gain control device in ultrasonic pulse transmission | |
| JPS5728433A (en) | Squelch system | |
| JPS57186843A (en) | Tone squelch voice monitoring system | |
| JPS5472611A (en) | Squelch control system | |
| JPS5784675A (en) | Facsimile absence receiver | |
| KR100216628B1 (en) | Transmitting noise reducing device in cellular phone | |
| JPS6420761A (en) | Telephone terminal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |