US3942181A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable-gain amplifier
Assignee: Thales SA
•
Filing: 1973-10-19
•
Granted: 1976-03-02
•
Expires: 1993-10-19
Abstract
Abstract A variable-gain amplifier comprises a transistor with an emitter connected in a degenerative emitter-follower circuit which includes a PIN diode traversed by a current injector in the form of an operational amplifier, the PIN diode forming part of a negative-feedback path extending from the output to the inverting input of the operational amplifier. To achieve a gain characteristic whose logarithm varies linearly with a control voltage, this control voltage is fed to the same inverting input through an amplifier circuit with an exponential characteristic, including another operational amplifier provided with an input transistor. A temperature-compensating circuit, preceding that input transistor, comprises still another operational amplifier having a further transistor inserted in its negative-feedback path. The variable-gain amplifier may be included in one of two conjugate (sum and difference) channels of a monopulse radar.
Inventors
- 👤 Francois Berrod
- 👤 Fernand Puverel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:55
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3052; H03G3/3073; H03G1/00; H03G1/0005; H03G1/0035; H03G1/0052; H03G1/0058
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
130 words
A variable-gain amplifier comprising: semiconductor means provided with an input electrode connected to a source of high-frequency signals and with two further electrodes including a reference electrode whose potential relative to that of said input electrode determines the conductivity of said semiconductor means, one of said further electrodes being connected to a load; degenerative circuitry connected to said reference electrode for applying thereto a negative-feedback voltage; a PIN diode in said degenerative circuitry; biasing means for said PIN diode including an operational amplifier provided with an inverting input, a non-inverting input, an output, and a negative-feedback path connected between said output and inverting input thereof, said PIN diode being inserted in said negative-feedback path; and a source of gain-controlling voltage connected to one of the inputs of said operational amplifier.
Claim 2
Dependent Claim
130 words
A variable-gain amplifier comprising: semiconductor means provided with an input electrode connected to a source of high-frequency signals and with two further electrodes including a reference electrode whose potential relative to that of said input electrode determines the conductivity of said semiconductor means, one of said further electrodes being connected to a load; degenerative circuitry connected to said reference electrode for applying thereto a negative-feedback voltage; a PIN diode in said degenerative circuitry; biasing means for said PIN diode including an operational amplifier provided with an inverting input, a non-inverting input, an output, and a negative-feedback path connected between said output and inverting input thereof, said PIN diode being inserted in said negative-feedback path; and a source of gain-controlling voltage connected to one of the inputs of said operational amplifier.
Claim 3
Dependent Claim
98 words
A variable-gain amplifier as defined in claim 1 wherein said semiconductor means comprises a first and a second transistor stage each having a base, an emitter and a collector, said input electrode being the base of said first transistor stage, said reference electrode being the emitter of said first transistor stage, said degenerative circuitry forming part of an emitter-follower connection for said first transistor stage and being coupled to the emitter of said second transistor stage, the emitter of said first transistor stage being connected to the load via the emitter and collector of said second transistor stage.
Claim 4
Dependent Claim
18 words
A variable-gain amplifier as defined in claim 2 wherein said transistor stages are of the same conductivity type.
Claim 5
Dependent Claim
22 words
A variable-gain amplifier as defined in claim 1 wherein said source of gain-controlling voltage comprises an amplifier circuit with an exponential characteristic.
Claim 6
Dependent Claim
23 words
A variable-gain amplfier as defined in claim 4 wherein said source of gain-controlling voltage further comprises a temperature-compensating circuit preceding said amplifier circuit.
Claim 7
Dependent Claim
25 words
A variable-gain amplifier as defined in claim 5 wherein said amplifier circuit and said temperature-compensating circuit comprise a second and a third operational amplifier, respectively.
Claim 8
Dependent Claim
48 words
A variable-gain amplifier as defined in claim 6 wherein said amplifier circuit includes an input transistor connected to said second operational amplifier, said temperature-compensating circuit including a further transistor inserted in a negative-feedback connection of said third operational amplifier, said further transistor being provided with a control-voltage input.
Claim 9
Dependent Claim
21 words
A variable-gain amplifier as defined in claim 7 wherein said input transistor and said further transistor are connected in series-opposed relationship.
Claim 10
Dependent Claim
146 words
In a monopulse radar having two conjugate channels, the improvement wherein one of said channels includes a variable-gain amplifier comprising: semiconductor means provided with an input electrode connected to a source of high-frequency signal and with two further electrodes including a reference electrode whose potential relative to that of said input electrode determines the conductivity of said semiconductor means, one of said further electrodes being connected to a load; degenerative circuitry connected to said reference electrode for applying thereto a negative-feedback voltage; a PIN diode in said degenerative circuitry; biasing means for said PIN diode including an operational amplifier provided with an inverting input, a noninverting input, and output, and a negative-feedback path connected between said output and inverting input thereof, said PIN diode being inserted in said negative-feedback path; and a source of gain-controlling voltage connected to one of the inputs of said operational amplifier.
Claim 11
Dependent Claim
146 words
In a monopulse radar having two conjugate channels, the improvement wherein one of said channels includes a variable-gain amplifier comprising: semiconductor means provided with an input electrode connected to a source of high-frequency signal and with two further electrodes including a reference electrode whose potential relative to that of said input electrode determines the conductivity of said semiconductor means, one of said further electrodes being connected to a load; degenerative circuitry connected to said reference electrode for applying thereto a negative-feedback voltage; a PIN diode in said degenerative circuitry; biasing means for said PIN diode including an operational amplifier provided with an inverting input, a noninverting input, and output, and a negative-feedback path connected between said output and inverting input thereof, said PIN diode being inserted in said negative-feedback path; and a source of gain-controlling voltage connected to one of the inputs of said operational amplifier.
Claim 12
Dependent Claim
88 words
The programmable controller as recited in claim 9 in which said scanner circuit includes control means for alternately executing a data output sequence and a data input sequence, said control means being connected to said interrupt means, connected to said data in gate means and connected to said data out gate means, and being operable to enable said interrupt means and said data out gate means during said data output sequence, and to enable said interrupt means and said data in gate means during said data input sequence.
References Cited (Backward Citations)
US3550028A
Cited
US3582807A
Cited
US3624561A
Cited
US3708699A
Cited
US3710270A
Cited
US3708754A
Cited
US3774118A
Cited
US3743770A
Cited
US3723894A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-02 | 1979-09-01 | 1980-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-02 | 1983-09-01 | 1984-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-02 | 1987-09-01 | 1988-03-02 | $7700.00 | Window Closed / Lapsed |