Patent US3846711A successfully refreshed from Google Patents.
US3846711A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic gain control circuit
Assignee: Hitachi Ltd
•
Filing: 1973-08-07
•
Granted: 1974-11-05
•
Expires: 1993-08-07
Abstract
Abstract An automatic gain control circuit which includes an amplifier portion for amplifying the automatic gain control signal, an impedance control portion driven by the output of the amplifier portion, a variable impedance portion provided separately from the amplifier portion and controlled by the impedance control portion, and an AC bypass portion arranged on the input side of the impedance control portion, whereby even when the control signal is at a low level, the gain control can be effected at a low distortion factor.
Inventors
- 👤 K Takahashi
- 👤 M Sato
- 👤 K Ohta
- 👤 T Takamiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:01
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H03G3/301; H03G3/3015
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
88 words
An automatic gain control circuit comprising amplifier means for amplifying an automatic gain control signal, variable impedance means having a non-linear voltage characteristic for providing a varying impedance in response to the amplified automatic gain control signal, an impedance control circuit connecting the output of said amplifier means to said variable impedance means, and bypass means including a plurality of forward biased PN junction devices series connected to the input of said impedance control circuit and having a non-linear voltage characteristic for bypassing AC signal components to ground.
Claim 2
Dependent Claim
88 words
An automatic gain control circuit comprising amplifier means for amplifying an automatic gain control signal, variable impedance means having a non-linear voltage characteristic for providing a varying impedance in response to the amplified automatic gain control signal, an impedance control circuit connecting the output of said amplifier means to said variable impedance means, and bypass means including a plurality of forward biased PN junction devices series connected to the input of said impedance control circuit and having a non-linear voltage characteristic for bypassing AC signal components to ground.
Claim 3
Dependent Claim
42 words
An automatic gain control circuit as defined in claim 1, wherein said amplifier means includes a voltage source, a first transistor connected to said voltage source and having its input electrode connected to an input terminal receiving said automatic gain control signal.
Claim 4
Dependent Claim
29 words
An automatic gain control circuit as defined in claim 2, wherein said amplifier means further includes a second transistor connected between said first transistor and said impedance control circuit.
Claim 5
Dependent Claim
39 words
An automatic gain control circuit as defined in claim 2, wherein said amplifier means further includes a first resistor connected between said first transistor and said voltage source and a second resistor connected between said first transistor and ground.
Claim 6
Dependent Claim
41 words
An automatic gain control circuit as defined in claim 4, wherein said impedance control circuit includes a second transistor connected between said voltage source and an output terminal and having an input electrode connected to the output of said amplifier means.
Claim 7
Dependent Claim
28 words
An automatic gain control circuit as defined in claim 5, wherein said impedance control circuit further includes a diode connected between said second transistor and said output terminal.
Claim 8
Dependent Claim
30 words
An automatic gain control circuit as defined in claim 6, wherein said variable impedance means includes a first pair of diodes connected in series between said output terminal and ground.
Claim 9
Dependent Claim
41 words
An automatic gain control circuit as defined in claim 7, wherein said PN junction devices of said bypass means include second and third pairs of series connected diodes connected in series between the input electrode of said third transistor and ground.
Claim 10
Dependent Claim
37 words
An automatic gain control circuit as defined in claim 1, wherein said PN junction devices of said bypass means include a plurality of diodes connected in series between the input of said impedance control circuit and ground.
Claim 11
Dependent Claim
43 words
An automatic gain control circuit as defined in claim 1, wherein the number of PN junction devices provided in said bypass means is equal to the number of forward biased PN junctions comprised in said variable impedance means and said impedance control circuit.
Claim 12
Dependent Claim
130 words
An automatic gain control circuit comprising amplifier means for amplifying an automatic gain control signal, variable impedance means having a non-linear voltage characteristic for providing a varying impedance in response to the amplified automatic gain control signal, an impedance control circuit connecting the output of said amplifier means to said variable impedance means, and bypass means connected to the input of said impedance control circuit and having a non-linear voltage characteristic for bypassing AC signal components to ground, wherein said impedance control circuit includes a first transistor connected between a voltage source and an output terminal and having an input electrode connected to the output of said amplifier means, said variable impedance means being connected to said output terminal in series with said impedance control circuit across said voltage source.
Claim 13
Dependent Claim
130 words
An automatic gain control circuit comprising amplifier means for amplifying an automatic gain control signal, variable impedance means having a non-linear voltage characteristic for providing a varying impedance in response to the amplified automatic gain control signal, an impedance control circuit connecting the output of said amplifier means to said variable impedance means, and bypass means connected to the input of said impedance control circuit and having a non-linear voltage characteristic for bypassing AC signal components to ground, wherein said impedance control circuit includes a first transistor connected between a voltage source and an output terminal and having an input electrode connected to the output of said amplifier means, said variable impedance means being connected to said output terminal in series with said impedance control circuit across said voltage source.
Claim 14
Dependent Claim
28 words
An automatic gain control circuit as defined in claim 11, wherein said impedance control circuit further includes a diode connected between said first transistor and said output terminal.
Claim 15
Dependent Claim
38 words
An automatic gain control circuit as defined in claim 11, wherein said variable impedance means includes a second transistor connected between said output terminal and ground, the base of said second transistor being connected to the collector thereof.
Claim 16
Dependent Claim
31 words
An automatic gain control circuit as defined in claim 13, wherein said bypass means includes third and fourth transistors connected in series and each having its base connected to its collector.
Claim 17
Dependent Claim
30 words
An automatic gain control circuit as defined in claim 11, wherein said variable impedance means includes a first pair of diodes connected in series between said output terminal and ground.
Claim 18
Dependent Claim
36 words
An automatic gain control circuit as defined in claim 15, wherein said bypass means includes second and third pairs of series connected diodes connected in series between the input electrode of said first transistor and ground.
Claim 19
Dependent Claim
30 words
An automatic gain control circuit as defined in claim 11, wherein said variable impedance means includes a first pair of diodes connected in series between said output terminal and ground.
References Cited (Backward Citations)
US3267388A
Cited
US3397324A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |