US3716801A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplifier with improved avc circuit
Assignee: Telefunken Electronic GmbH
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Filing: 1970-07-07
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Granted: 1973-02-13
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Expires: 1990-07-07
Abstract
Abstract An improved AVC circuit for an alternating voltage amplifier which prevents over-control, and thus temporary blocking of the amplifier circuit, upon the occurrence of a sudden large increase in the amplitude of the input signal to the amplifier. The control voltage generating arrangement of the AVC circuit is constructed so that the time constant of the control voltage is increased proportionately to the increase of the output voltage from the amplifier when ever the output voltage exceeds a predetermined value.
Inventors
- 👤 W Minner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:49
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
247 words
In an amplifier for alternating voltages which amplifier is provided with an automatic volume control (AVC) circuit responsive to the output signal thereof, and wherein the time constant of the stage or stages of the amplifier which is controlled by the AVC voltage is sufficiently large relative to the normal time constant of the AVC circuit so that temporary blocking of the amplifier would normally occur upon the occurrence of a sudden large increase in the amplifier input voltage, the improvement wherein said AVC circuit comprises: a collector-detector circuit including a transistor which is arranged only in the AVC-voltage signal path but not in the forward signal transmission path of said amplifier, said transistor having its base connected to the output of said amplifier and its emitter-collector circuit connected across a source of operating d.c. potential; a charging capacitor connected in the emitter circuit path of said transistor for furnishing the AVC circuit control voltage; and means for limiting the charging current to said capacitor comprising an ohmic resistor connected in the collector circuit path of said transistor, whereby the time constant of said AVC circuit is increased proportionally to the increase in the output voltage signal of said amplifier above a predetermined value so that with increasing input voltage to said amplifier the time constant of the AVC circuit increases to such an extent that, independent of the alternating input signal to said amplifier, overcontrol of said amplifier, and thus blocking of said amplifier, is avoided.
Claim 2
Dependent Claim
247 words
In an amplifier for alternating voltages which amplifier is provided with an automatic volume control (AVC) circuit responsive to the output signal thereof, and wherein the time constant of the stage or stages of the amplifier which is controlled by the AVC voltage is sufficiently large relative to the normal time constant of the AVC circuit so that temporary blocking of the amplifier would normally occur upon the occurrence of a sudden large increase in the amplifier input voltage, the improvement wherein said AVC circuit comprises: a collector-detector circuit including a transistor which is arranged only in the AVC-voltage signal path but not in the forward signal transmission path of said amplifier, said transistor having its base connected to the output of said amplifier and its emitter-collector circuit connected across a source of operating d.c. potential; a charging capacitor connected in the emitter circuit path of said transistor for furnishing the AVC circuit control voltage; and means for limiting the charging current to said capacitor comprising an ohmic resistor connected in the collector circuit path of said transistor, whereby the time constant of said AVC circuit is increased proportionally to the increase in the output voltage signal of said amplifier above a predetermined value so that with increasing input voltage to said amplifier the time constant of the AVC circuit increases to such an extent that, independent of the alternating input signal to said amplifier, overcontrol of said amplifier, and thus blocking of said amplifier, is avoided.
Claim 3
Dependent Claim
247 words
In an amplifier for alternating voltages which amplifier is provided with an automatic volume control (AVC) circuit responsive to the output signal thereof, and wherein the time constant of the stage or stages of the amplifier which is controlled by the AVC voltage is sufficiently large relative to the normal time constant of the AVC circuit so that temporary blocking of the amplifier would normally occur upon the occurrence of a sudden large increase in the amplifier input voltage, the improvement wherein said AVC circuit comprises: a collector-detector circuit including a transistor which is arranged only in the AVC-voltage signal path but not in the forward signal transmission path of said amplifier, said transistor having its base connected to the output of said amplifier and its emitter-collector circuit connected across a source of operating d.c. potential; a charging capacitor connected in the emitter circuit path of said transistor for furnishing the AVC circuit control voltage; and means for limiting the charging current to said capacitor comprising an ohmic resistor connected in the collector circuit path of said transistor, whereby the time constant of said AVC circuit is increased proportionally to the increase in the output voltage signal of said amplifier above a predetermined value so that with increasing input voltage to said amplifier the time constant of the AVC circuit increases to such an extent that, independent of the alternating input signal to said amplifier, overcontrol of said amplifier, and thus blocking of said amplifier, is avoided.
Claim 4
Dependent Claim
247 words
In an amplifier for alternating voltages which amplifier is provided with an automatic volume control (AVC) circuit responsive to the output signal thereof, and wherein the time constant of the stage or stages of the amplifier which is controlled by the AVC voltage is sufficiently large relative to the normal time constant of the AVC circuit so that temporary blocking of the amplifier would normally occur upon the occurrence of a sudden large increase in the amplifier input voltage, the improvement wherein said AVC circuit comprises: a collector-detector circuit including a transistor which is arranged only in the AVC-voltage signal path but not in the forward signal transmission path of said amplifier, said transistor having its base connected to the output of said amplifier and its emitter-collector circuit connected across a source of operating d.c. potential; a charging capacitor connected in the emitter circuit path of said transistor for furnishing the AVC circuit control voltage; and means for limiting the charging current to said capacitor comprising an ohmic resistor connected in the collector circuit path of said transistor, whereby the time constant of said AVC circuit is increased proportionally to the increase in the output voltage signal of said amplifier above a predetermined value so that with increasing input voltage to said amplifier the time constant of the AVC circuit increases to such an extent that, independent of the alternating input signal to said amplifier, overcontrol of said amplifier, and thus blocking of said amplifier, is avoided.
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) | 1976-02-13 | 1976-08-14 | 1977-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-13 | 1980-08-14 | 1981-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-13 | 1984-08-14 | 1985-02-13 | $7700.00 | Window Closed / Lapsed |