US3828267A
Expired / Lapsed
US
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Muting circuit
Assignee: Sony Corp
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Filing: 1973-05-15
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Granted: 1974-08-06
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Expires: 1993-05-15
Abstract
Abstract A voltage dividing circuit including first and second transistors connected in series is connected between a first output terminal of one polarity of a bridge rectifier circuit and a second output terminal of the opposite polarity of a voltage regulator connected to the bridge rectifier circuit. A first time constant circuit is connected between the base of a first one of the transistors and the first output terminal and a second time constant circuit is connected between the base electrode of the second transistor and the circuit ground. A muting transistor is connected in shunt with the signal transmission line and its base is connected between the first output terminal and the first transistor. When power is applied to the circuit by the closing of a power switch the first transistor is initially made nonconductive during a predetermined period by the operation of the first time constant circuit so that the base electrode of the muting transistor is supplied with a muting signal to make it conductive and thereby mute signals on the transmission line. When power to the circuit is interrupted, as by the opening of the power switch, the second transistor is made non-conductive by the second time constant circuit for a predetermined time so that power stored in the voltage regulating circuit is supplied to the base electrode of the muting transistor to thereby again mute signals on the transmission line.
Inventors
- 👤 K Tsurushima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:52
CPC Classifications
H; H04; H04R; H04R3/00; H04R3/007; G; G11; G11B; G11B5/00; H03; H03F; H03F1/00; H03F1/30; H03F1/305; H03G; H03G1/00; H03G1/0005; H03G1/0035; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H03G3/301; H03G3/3015; H03G3/34; H03G3/348; H03K; H03K17/00; H03K17/28; H04S; H04S3/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
138 words
A muting circuit for use with a signal transmission path and a power supply, the muting circuit comprising: a. a muting element connected to the signal transmission means; b. a muting signal producing circuit including first and second switching elements connected in series with each other and connected across an output from the power supply and circuit means connected between the power supply and the first and second switching elements for producing a first muting signal after a predetermined period in response to the application of power from an external source to the power supply and a second muting signal in response to the interruption of power to the power supply, respectively; and c. means connected between the muting signal producing circuit and the muting element for supplying the first and second muting signals to the muting element.
Claim 2
Dependent Claim
138 words
A muting circuit for use with a signal transmission path and a power supply, the muting circuit comprising: a. a muting element connected to the signal transmission means; b. a muting signal producing circuit including first and second switching elements connected in series with each other and connected across an output from the power supply and circuit means connected between the power supply and the first and second switching elements for producing a first muting signal after a predetermined period in response to the application of power from an external source to the power supply and a second muting signal in response to the interruption of power to the power supply, respectively; and c. means connected between the muting signal producing circuit and the muting element for supplying the first and second muting signals to the muting element.
Claim 3
Dependent Claim
142 words
In a muting circuit for use with a power supply having output terminals, a signal transmission means for transmitting signals and a muting element having a control terminal and connected to the signal transmission means, a muting signal producing circuit comprising: a. first and second transistors connected in series with each other and to the output terminals of the power source; b. first circuit means connected to the first transistor for causing the first transistor to be non-conductive during a predetermined time period in response to the application of power from an external source to the power supply; c. second circuit means connected to the second transistor for causing the second transistor to be non-conductive in response to the interruption of power to the power supply; and d. means connected between the first transistor and the control terminal of the muting element.
Claim 4
Dependent Claim
142 words
In a muting circuit for use with a power supply having output terminals, a signal transmission means for transmitting signals and a muting element having a control terminal and connected to the signal transmission means, a muting signal producing circuit comprising: a. first and second transistors connected in series with each other and to the output terminals of the power source; b. first circuit means connected to the first transistor for causing the first transistor to be non-conductive during a predetermined time period in response to the application of power from an external source to the power supply; c. second circuit means connected to the second transistor for causing the second transistor to be non-conductive in response to the interruption of power to the power supply; and d. means connected between the first transistor and the control terminal of the muting element.
Claim 5
Dependent Claim
23 words
A muting circuit as recited in claim 2 wherein the first and second circuit means are time constant circuits, each including a capacitor.
Claim 6
Dependent Claim
23 words
A muting circuit as recited in claim 2 wherein the muting element is connected between the signal transmission means and the circuit ground.
Claim 7
Dependent Claim
26 words
A muting circuit as recited in claim 2 wherein the signal transmission means includes an amplifier which is supplied with DC voltage from the power source.
Claim 8
Dependent Claim
25 words
A muting circuit as recited in claim 2 wherein the muting element is a field effect transistor connected in series with the signal transmission means.
Claim 9
Dependent Claim
214 words
A muting circuit for use with a signal transmission path and a DC power supply of the type having a circuit ground, a first terminal for supplying a voltage of one polarity and a second terminal for supplying a voltage of the opposite polarity a predetermined time after the application of power from the external source to the power supply, the muting circuit comprising a first switching element connected to the signal transmission path to selectively interrupt the passage of signals through the transmission Path, second and third switching elements connected in series between the first and second power supply terminals, first means connected to the first power supply terminal for causing the second switching element to change from a non-conductive to a conductive state a predetermined time after the voltage of one polarity is initially supplied, second means connected to the second power supply terminal and the circuit ground for causing the third switching element to change from a conductive to a non-conductive state when the voltage of the opposite polarity ceases, and means connected between the first power supply terminal and the second switching element for causing the first switching element to interrupt the passage of signals through the transmission path when either of the second and third switching elements is non-conductive.
Claim 10
Dependent Claim
214 words
A muting circuit for use with a signal transmission path and a DC power supply of the type having a circuit ground, a first terminal for supplying a voltage of one polarity and a second terminal for supplying a voltage of the opposite polarity a predetermined time after the application of power from the external source to the power supply, the muting circuit comprising a first switching element connected to the signal transmission path to selectively interrupt the passage of signals through the transmission Path, second and third switching elements connected in series between the first and second power supply terminals, first means connected to the first power supply terminal for causing the second switching element to change from a non-conductive to a conductive state a predetermined time after the voltage of one polarity is initially supplied, second means connected to the second power supply terminal and the circuit ground for causing the third switching element to change from a conductive to a non-conductive state when the voltage of the opposite polarity ceases, and means connected between the first power supply terminal and the second switching element for causing the first switching element to interrupt the passage of signals through the transmission path when either of the second and third switching elements is non-conductive.
Claim 11
Dependent Claim
18 words
A muting circuit as recited in claim 7 wherein the first, second and third switching elements are transistors.
Claim 12
Dependent Claim
52 words
A muting circuit as recited in claim 8 wherein the first means includes a resistor connected between the base electrode of the second switching element transistor and the first power supply terminal and a capacitor connected between the base electrode of the second switching element transistor and the second power supply terminal.
Claim 13
Dependent Claim
50 words
A muting circuit as recited in claim 8 wherein the second means includes a resistor connected between the base electrode of the third switching element transistor and the first power supply terminal and a capacitor connected between the base electrode of the third switching element transistor and the circuit ground.
Claim 14
Dependent Claim
45 words
A muting circuit as recited in claim 7 further comprising a plurality of transmission paths and a plurality of muting elements corresponding to the first switching element, each muting element being connected to a separage transmission path but controlled simultaneously with the first switching element.
References Cited (Backward Citations)
US3375446A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-05 | 1978-02-04 | 1978-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-05 | 1982-02-04 | 1982-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-05 | 1986-02-04 | 1986-08-06 | $7700.00 | Window Closed / Lapsed |