US3891933A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplifier with signal clipping indicator and/or protective circuit
Assignee: Sony Corp
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Filing: 1974-02-04
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Granted: 1975-06-24
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Expires: 1994-02-04
Abstract
Abstract An amplifier with a signal clipping indicator and/or a protective circuit having an amplifying stage with a negative feedback loop which amplifies an input signal applied to the input terminal thereof and compares the input signal with a negative feedback signal for producing a control signal when the waveforms of the two signals are different, a signal clipping indicator controlled by the control signal for indicating the clipping state of the amplifier, and a protective circuit controlled by the control signal for protecting the amplifier from injury. By way of example, an indicating circuit using a monostable multivibrator and a photodiode or luminous diode may be employed as the indicator.
Inventors
- 👤 Tadao Suzuki
- 👤 Hirohito Kawada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:31
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/30; H03F3/3069; H03F3/3071; H03F1/00; H03F1/52
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
208 words
An audio amplifier with a signal clipping and/or a protective circuit comprising, a first differential amplifier comprising first and second transistors with their emitters coupled together, an input terminal connected to the base of said first transistor, positive and negative biasing terminals with said positive terminal coupled to the collectors of said first and second transistors, a third transister connected between the emitters of said first and second transistors and said negative biasing terminal, a second differential amplifier comprising fourth and fifth transistors with their emitters coupled to said positive biasing terminal and their collectors to said negative biasing terminal, the base of said fourth transistor connected to the collector of said second transistor, the base of said fifth transistor connected to the collector of said first transistor, a push pull output stage connected to said fourth and fifth transistors, an output terminal connected to said output stage and connected to the base of said second transistor and supplying a negative feedback signal thereto, a pair of detecting terminals connected, respectively, to the collectors of said fourth and fifth transistors, and protective circuit means connected to said pair of detector terminals to protect said audio amplifier when the signal at said pair of detecting terminals exceeds predtermined limits.
Claim 2
Dependent Claim
208 words
An audio amplifier with a signal clipping and/or a protective circuit comprising, a first differential amplifier comprising first and second transistors with their emitters coupled together, an input terminal connected to the base of said first transistor, positive and negative biasing terminals with said positive terminal coupled to the collectors of said first and second transistors, a third transister connected between the emitters of said first and second transistors and said negative biasing terminal, a second differential amplifier comprising fourth and fifth transistors with their emitters coupled to said positive biasing terminal and their collectors to said negative biasing terminal, the base of said fourth transistor connected to the collector of said second transistor, the base of said fifth transistor connected to the collector of said first transistor, a push pull output stage connected to said fourth and fifth transistors, an output terminal connected to said output stage and connected to the base of said second transistor and supplying a negative feedback signal thereto, a pair of detecting terminals connected, respectively, to the collectors of said fourth and fifth transistors, and protective circuit means connected to said pair of detector terminals to protect said audio amplifier when the signal at said pair of detecting terminals exceeds predtermined limits.
Claim 3
Dependent Claim
37 words
An amplifier with a signal clipping indicator and/or a protective circuit according to claim 1, further including a third differential amplifier comprising sixth and seventh transistors connected between said second differential amplifier and said push-pull amplifying stage.
Claim 4
Dependent Claim
72 words
An amplifier with a signal clipping indicator and/or a protective circuit according to claim 2, wherein said protective circuit means comprises an eighth switching transistor with base coupled to said pair of detector terminals, a monostable multivibrator and an indicator, said eighth switching transistor coupled to said monostable multivibrator to invert is ON state and said indicator connected to said monostable multivibrator to indicate when said multivibrator has its ON stage inverted.
Claim 5
Dependent Claim
35 words
An amplifier with a signal clipping indicator and/or a protective circuit according to claim 3 wherein including a pair of diodes connected between pair of detector terminals and the base of said eighth switching transistor.
Claim 6
Dependent Claim
24 words
An amplifier according to claim 4 wherein said indicator comprises a red light which is illuminated when said multivibrator has its ON stage inverted.
Claim 7
Dependent Claim
26 words
An amplifier aCcording to claim 5 wherein said indicator includes a green light which is illuminated when said multivibrator does not have its ON stage inverted.
Claim 8
Dependent Claim
73 words
An amplifier according to claim 1 wherein said protective circuit includes a sixth transistor connected to said pair of detector terminals and under normal satisfactory operating conditions biased to the non-conducting state, a relay connected to said sixth transistor and energized when said sixth transistor conducts, and a switch connected between said output terminal and said push-pull output stage and said relay controlling said switch to open it when said sixth transistor conducts.
Claim 9
Dependent Claim
206 words
An amplifier with a signal clipping indication and/or a protective circuit comprising: a. a voltage source; b. a first differential amplifier having first and second transistors each having base, emitter and collector, the emitters of said first and second transistors being connected together and connected to one terminal of said voltage source through a common emitter impedance, the base of said first transistor being supplied with an input signal to be amplified; c. first and second resistors each connected between the other terminal of said voltage source and each collector of said first and second transistors; d. signal output means connected to at least one of said first and second resistors; e. feedback means connected between said signal output means and the base of said second transistor so as to supply a feedback signal having the same phase and amplitude as said input signal supplied to the base of said first transistor; and f. means for detecting an abrupt voltage change at one of said collectors of said first and second transistors and for producing a control signal when an unbalance exists between said input signal and said feedback signal whereby said control signal is indicative of a clipping state produced in said signal output means.
Claim 10
Dependent Claim
206 words
An amplifier with a signal clipping indication and/or a protective circuit comprising: a. a voltage source; b. a first differential amplifier having first and second transistors each having base, emitter and collector, the emitters of said first and second transistors being connected together and connected to one terminal of said voltage source through a common emitter impedance, the base of said first transistor being supplied with an input signal to be amplified; c. first and second resistors each connected between the other terminal of said voltage source and each collector of said first and second transistors; d. signal output means connected to at least one of said first and second resistors; e. feedback means connected between said signal output means and the base of said second transistor so as to supply a feedback signal having the same phase and amplitude as said input signal supplied to the base of said first transistor; and f. means for detecting an abrupt voltage change at one of said collectors of said first and second transistors and for producing a control signal when an unbalance exists between said input signal and said feedback signal whereby said control signal is indicative of a clipping state produced in said signal output means.
Claim 11
Dependent Claim
74 words
An amplifier with a signal clipping indication and/or a protective circuit according to claim 8, wherein said signal output means comprises a push-pull amplifying stage having input and output terminals, said input terminal being connected to said either one of said first and second resistors and a load connected to said output terminal, said feedback means is provided between said output terminal of said push-pull amplifying stage and the base of said second transistor.
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) | 1978-06-23 | 1978-12-23 | 1979-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-23 | 1982-12-23 | 1983-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-23 | 1986-12-23 | 1987-06-24 | $7700.00 | Window Closed / Lapsed |