US3745262A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplifier arrangement for telephone instrument
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1971-12-01
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Granted: 1973-07-10
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Expires: 1991-12-01
Abstract
Abstract An amplifier arrangement for controlling the output level of an amplifier used in a two-wire line telephone system comprises an attenuation circuit, a memory circuit, an integration circuit and a test device. The output level of the amplifier is tested by the test device and if the output level is too high activates the integration circuit. When the output voltage of the integration circuit exceeds a certain value the memory circuit changes state to (1) activate the attenuation circuit so that the output level of the amplifier is decreased, and (2) re-set the integration circuit. The memory circuit remains in its changed state until the direct voltage level of the two-wire line is essentially changed in which case the memory circuit is re-set to the original state and the attenuation circuit is no longer activated and the integration circuit may again be started by the test device.
Inventors
- 👤 U Brolin
- 👤 O Lindgren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:59
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H04; H04M; H04M9/00; H04M9/08; H04M9/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
276 words
Volume controlled telephone instrument comprising: terminal means adapted to be connected to a subscriber line; a speaker means; a receiver circuit connected between said terminal means and said speaker means comprising a speech current amplifier and a signal-controllable signal attenuator; a microphone; a transmitter circuit connected between said microphone and said terminal means comprising an amplifier means; and an automatic volume control means for controlling the operation of said signal-controllable signal attenuator comprising a signal level test means having an input connected to said speech current amplifier and an output, said signal level test operating in a binary manner dependent on a predetermined threshold level of the speech signal from said speech current amplifier, an integrating circuit means having an input connected to the output of said signal level test means and operative to generate an amplitude increasing signal as long as said signal level test means senses that the speech signal is above said predetermined threshold level, and a memory means comprising a bistable control signal generator means having a set input connected to said integrating circuit means, a clear input connected to said terminal means and a control signal output for generating an attenuating control signal having a first valve when set to a first state when the amplitude of the signal generated by said integrating circuit means exceeds a given level and for generating the attenuating control signal having a second value when cleared to a second state in response to a particular change in the direct voltage on the subscriber line, and connecting means for connecting said control signal output of said bistable control signal generator means to said signal-controllable signal attenuator.
Claim 2
Dependent Claim
276 words
Volume controlled telephone instrument comprising: terminal means adapted to be connected to a subscriber line; a speaker means; a receiver circuit connected between said terminal means and said speaker means comprising a speech current amplifier and a signal-controllable signal attenuator; a microphone; a transmitter circuit connected between said microphone and said terminal means comprising an amplifier means; and an automatic volume control means for controlling the operation of said signal-controllable signal attenuator comprising a signal level test means having an input connected to said speech current amplifier and an output, said signal level test operating in a binary manner dependent on a predetermined threshold level of the speech signal from said speech current amplifier, an integrating circuit means having an input connected to the output of said signal level test means and operative to generate an amplitude increasing signal as long as said signal level test means senses that the speech signal is above said predetermined threshold level, and a memory means comprising a bistable control signal generator means having a set input connected to said integrating circuit means, a clear input connected to said terminal means and a control signal output for generating an attenuating control signal having a first valve when set to a first state when the amplitude of the signal generated by said integrating circuit means exceeds a given level and for generating the attenuating control signal having a second value when cleared to a second state in response to a particular change in the direct voltage on the subscriber line, and connecting means for connecting said control signal output of said bistable control signal generator means to said signal-controllable signal attenuator.
Claim 3
Dependent Claim
34 words
The volume controlled telephone instrument of claim 1 further comprising manually operable means connected to said clear input of said bistable control signal generator means for independnetly clearing the latter to the second state.
Claim 4
Dependent Claim
90 words
The volume controlled telephone instrument of claim 1 wherein said connecting means comprises a signal comparator means having first and second inputs for receiving the signals whose amplitudes are to be compared and an output for transmitting a control signal having an amplitude related to the relative amplitudes of the signals received at said first and second inputs, said first input being connected to said receiver circuit, said second input being connected to the output of said bistable control signal generator and said output being connected to signal-controllable signal attenuator.
Claim 5
Dependent Claim
61 words
The volume controlled telephone instrument of claim 1 wherein the amplifier means connecting said microphone to said terminal means is a gain-controlled amplifier whose gain is controllable by a control signal received at a control signal input and further comprising connecting means for connecting the control signal input of said gain-controlled amplifier to the output of said bistable control signal generator.
Claim 6
Dependent Claim
90 words
The volume controlled telephone instrumenT of claim 4 wherein said connecting means comprises a signal comparator means having first and second inputs for receiving the signals whose amplitudes are to be compared and an output for transmitting a control signal having an amplitude related to the relative amplitudes of the signals received at said first and second inputs, said first input being connected to said transmitter circuit, said second input being connected to the output of said bistable control signal generator and said output being connected to signal-controllable signal attenuator.
Claim 7
Dependent Claim
56 words
The volume control instrument of claim 1 wherein said integrating circuit means includes two alternately operable timing circuits, one having a longer time constant than the other, said one being operable when the speech signal is above said predetermined threshold level and said other being operable when the speech signal is below said predetermined threshold level.
Claim 8
Dependent Claim
221 words
The volume control instrument of claim 1 wherein said integrating circuit means includes a clearing input and said memory means comprises a plurality of bistable control signal generator means each having a set input connected to said integrating circuit means, a clear input connected to said terminal means and a control signal output for generating an attentuating control signal having a first value when set to a first state when the amplitude of the signal generated by said integrating circuit means exceeds a given level and for generating the attenuating control signal with a second value when cleared to a second state in response to a particular change in the direct voltage on the subscriber line, all but one of said bistable control signal generator means having a further input for sensitizing its set input to receive signals from said integrating means only when a different other one of said bistable control signal generator means is in said first state, means for connecting the outputs of said bistable control signal generator means to the clearing input of said integrating circuit means for clearing the latter each time one of said bistable control signal generator means is switched to said first state, and signal summing means for connecting the outputs of said bistable control signal generator means to said signal-controllable signal attenuator.
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) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |