US3912946A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic-volume-control system for a-c signals
Assignee: STMicroelectronics SRL
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Filing: 1974-10-21
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Granted: 1975-10-14
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Expires: 1994-10-21
Abstract
Abstract An AVC system for alternating-current signals, generated by a constant-gain amplifier, comprises an R/C network preceded by a diode and followed by a set of monolithically integrated transistors of like conductivity type (NPN) connected in two cascaded groups across a source of direct current. Each group consists of a pilot transistor and a final transistor, the pilot transistor of the first group having its base connected to the capacitor of the R/C network whereas the emitter of the final transistor of that group is tied to the base of the pilot transistor and to the collector of the final transistor of the second group. Corresponding transistors of the two groups have the same direct-current gain, and the combined direct current drawn by the transistors of the first group substantially equals that drawn by the transistors of the second group.
Inventors
- 👤 Rinaldo Graziadei
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:09
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/24; H03G; H03G1/00; H03G1/0005; H03G1/0035; H03G1/0082; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H03G3/301; H03G3/3015
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
163 words
An automatic-volume-control system comprising: a source of alternating-current signals; rectifying means connected to said source; a time-constant network including a storage capacitor connected to said source through said rectifying means; a first group of n cascaded transistors including a first pilot transistor and a first final transistor, n being an integer greater than one; a second group of n cascaded transistors including a second pilot transistor and a second final transistor; an operating circuit for said transistors including a directcurrent power supply with two terminals, said first pilot transistor having an input electrode tied to said capacitor, said final transistors being connected in tandem across said terminals and forming a junction, said second pilot transistor having an input electrode tied to said junction, corresponding transistors of said groups being of like conductivity type and having substantially the same direct-current gain; and a load circuit connected to said junction for differential energization by said final transistors with an attenuated replica of said alternating-current signals.
Claim 2
Dependent Claim
163 words
An automatic-volume-control system comprising: a source of alternating-current signals; rectifying means connected to said source; a time-constant network including a storage capacitor connected to said source through said rectifying means; a first group of n cascaded transistors including a first pilot transistor and a first final transistor, n being an integer greater than one; a second group of n cascaded transistors including a second pilot transistor and a second final transistor; an operating circuit for said transistors including a directcurrent power supply with two terminals, said first pilot transistor having an input electrode tied to said capacitor, said final transistors being connected in tandem across said terminals and forming a junction, said second pilot transistor having an input electrode tied to said junction, corresponding transistors of said groups being of like conductivity type and having substantially the same direct-current gain; and a load circuit connected to said junction for differential energization by said final transistors with an attenuated replica of said alternating-current signals.
Claim 3
Dependent Claim
33 words
A system as defined in claim 1 wherein each of said transistors has a base, an emitter and a collector, said input electrodes being bases, all said transistors being of like conductivity type.
Claim 4
Dependent Claim
93 words
A system as defined in claim 2 wherein n 2, the collectors of said first and second pilot transistors and of said first final transistor being tied to one of said terminals, the emitter of said second final transistor being tied to the other of said terminals, the emitter of each pilot transistor being tied to the base of the final transistor of the same group; said junction being connected to the emitter of said first final transistoR, the base of said second pilot transistor and the collector of said second final transistor.
Claim 5
Dependent Claim
26 words
A system as defined in claim 3 wherein the direct-current gain of said pilot transistors is substantially higher than the direct-current gain of said final transistors.
Claim 6
Dependent Claim
14 words
A system as defined in claim 1 wherein said source is a constant-gain amplifier.
Claim 7
Dependent Claim
17 words
A system as defined in claim 1 wherein said transistors are part of a monolithically integrated module.
References Cited (Backward Citations)
US3582681A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-13 | 1979-04-14 | 1979-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-13 | 1983-04-14 | 1983-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-13 | 1987-04-14 | 1987-10-14 | $7700.00 | Window Closed / Lapsed |