US3706846A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Television receiver intermediate frequency amplifier circuitry
Assignee: GTE Sylvania Inc
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Filing: 1970-12-07
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Granted: 1972-12-19
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Expires: 1990-12-07
Abstract
Abstract An intermediate frequency amplifier, utilizing a common base transistor amplifier, which changes the intermediate frequency response with gain to improve the weak signal (maximum gain) performance of a television receiver is disclosed. Series and/or parallel resonant circuits are damped by the input impedance of the transistor to increase or decrease the Q of the circuit response.
Inventors
- 👤 Karol Siwko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:29
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/189; H03F3/19; H03G; H03G9/00; H03G9/20; H03G9/24; H04; H04N; H04N5/00; H04N5/44; H04N5/52
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
166 words
In a television receiver having radio frequency, intermediate frequency, audio, video, synchronizing and control circuitry wherein said control circuitry includes an automatic gain control circuit, improved intermediate frequency circuitry comprising: an amplifier stage including a transistor means having an input means and connected in a common base configuration and a resonant circuit connected to said input means of said transistor means, said resonant circuit including inductance means and capacitance means and the input impedance of said transistor means providing series damping of said resonant circuit; and means connecting said automatic gain control circuit to said amplifier stage for varying the input impedance of said transistor means in accordance with an automatic gain control bias signal from said automatic gain control circuit for decreasing the frequency response bandwidth and peaking the portion of the frequency response including the video carrier intermediate frequency when the gain of said amplifier stage is increased relative to the frequency response when the gain of said amplifier stage is at a minimum.
Claim 2
Dependent Claim
166 words
In a television receiver having radio frequency, intermediate frequency, audio, video, synchronizing and control circuitry wherein said control circuitry includes an automatic gain control circuit, improved intermediate frequency circuitry comprising: an amplifier stage including a transistor means having an input means and connected in a common base configuration and a resonant circuit connected to said input means of said transistor means, said resonant circuit including inductance means and capacitance means and the input impedance of said transistor means providing series damping of said resonant circuit; and means connecting said automatic gain control circuit to said amplifier stage for varying the input impedance of said transistor means in accordance with an automatic gain control bias signal from said automatic gain control circuit for decreasing the frequency response bandwidth and peaking the portion of the frequency response including the video carrier intermediate frequency when the gain of said amplifier stage is increased relative to the frequency response when the gain of said amplifier stage is at a minimum.
Claim 3
Dependent Claim
48 words
Intermediate frequency circuitry as defined in claim 1 wherein said resonant circuit includes a capacitance means conNected in parallel with said input means of said transistor means whereby the resonant frequency of said resonant circuit varies in response to variations of the input impedance of said transistor means.
Claim 4
Dependent Claim
68 words
Intermediate frequency circuitry as defined in claim 1 wherein said resonant circuit is doubly tuned with a first resonant frequency at the video carrier intermediate frequency when the gain of said amplifier stage is maximum and a second resonant frequency at the audio carrier intermediate frequency, the frequency response bandwidth of each peak of said resonant circuit being decreased in response to the automatic gain control bias signal.
Claim 5
Dependent Claim
99 words
Intermediate frequency circuitry as defined in claim 1 including: a second amplifier stage including a second transistor means and a second resonant circuit including an inductance means and a capacitive means connected to said second transistor means, the input impedance of said second transistor means providing parallel damping of said second resonant circuit; and means connecting said automatic gain control circuit to said second amplifier stage for varying the input impedance of said second transistor means in accordance with the automatic gain control bias signal to increase the frequency response bandwidth of said second amplifier stage with increasing gain.
Claim 6
Dependent Claim
99 words
Intermediate frequency circuitry as defined in claim 3 including: a second amplifier stage including a second transistor means and a second resonant circuit including an inductive means and a capacitive means connected to said second transistor means, the input impedance of said second transistor means providing parallel damping of said second resonant circuit; and means connecting said automatic gain control circuit to said second amplifier stage for varying the input impedance of said second transistor means in accordance with the automatic gain control bias signal to increase the frequency response bandwidth of said second amplifier stage with increasing gain.
Claim 7
Dependent Claim
22 words
Intermediate frequency circuitry as defined in claim 5 wherein said first-named transistor means and said second transistor means are connected in cascade.
Claim 8
Dependent Claim
35 words
Intermediate frequency circuitry as defined in claim 5 wherein said second amplifier stage has a resonant frequency at a frequency intermediate the frequencies of said first and second resonant frequencies of said first-named amplifier stage.
Claim 9
Dependent Claim
177 words
In a television receiver an intermediate frequency amplifier comprising: an amplifier stage having a tuned circuit including an inductance means and a capacitance means and a transistor biased as a common base amplifier connected to said tuned circuit whereby the input impedance of said transistor provides series damping of said tuned circuit; and an automatic gain control means for providing an automatic gain control bias signal to said amplifier stage for varying the bias of said transistor in accordance with the strength of the signal being amplified and further varying the input impedance of said transistor to thereby vary the damping of said tuned circuit and the bandwidth of the frequency response of said amplifier stage by peaking the frequency response at the intermediate frequency of the video carrier to increase the amplitude of the video signal in the frequency spectrum near the video carrier relative to the amplitude of the video signal in the remaining portion of the intermediate frequency spectrum when the gain of said transistor is increased by said automatic gain control bias signal.
Claim 10
Dependent Claim
177 words
In a television receiver an intermediate frequency amplifier comprising: an amplifier stage having a tuned circuit including an inductance means and a capacitance means and a transistor biased as a common base amplifier connected to said tuned circuit whereby the input impedance of said transistor provides series damping of said tuned circuit; and an automatic gain control means for providing an automatic gain control bias signal to said amplifier stage for varying the bias of said transistor in accordance with the strength of the signal being amplified and further varying the input impedance of said transistor to thereby vary the damping of said tuned circuit and the bandwidth of the frequency response of said amplifier stage by peaking the frequency response at the intermediate frequency of the video carrier to increase the amplitude of the video signal in the frequency spectrum near the video carrier relative to the amplitude of the video signal in the remaining portion of the intermediate frequency spectrum when the gain of said transistor is increased by said automatic gain control bias signal.
Claim 11
Dependent Claim
59 words
An amplifier as defined in claim 8 wherein said tuned circuit is doubly tuned with a first resonant frequency approximately at the video carrier intermediate frequency and a second resonant frequency approximately at the audio carrier intermediate frequency, the frequency response bandwidth of each peak of said tuned circuit decreasing in response to decreased input impedance of said transistor.
Claim 12
Dependent Claim
109 words
An amplifier as defined in claim 8 including: a second amplifier stage having a second tUned circuit and a second transistor biased as a common base amplifier connected to said second tuned circuit whereby the input impedance of said second transistor damps said second tuned circuit; and means connecting said second amplifier stage to said automatic gain control means for varying the bias of said second transistor in accordance with the strength of the signal being amplified and further varying the input impedance of said second transistor to thereby vary the damping of said second tuned circuit and the bandwidth of the frequency response of said second amplifier stage.
Claim 13
Dependent Claim
97 words
An amplifier as defined in claim 10 wherein said first-named tuned circuit is doubly tuned with a first resonant frequency at the video carrier intermediate frequency and a second resonant frequency at the audio carrier intermediate frequency when the gain of said first-named amplifier stage is maximum, the frequency response bandwidth of each peak of said first-named tuned circuit decreasing in response to decreased input impedance of said first-named transistor, and said second tuned circuit has a resonant frequency at a frequency intermediate the frequency of said first and second resonant frequencies of said first-named tuned circuit.
Claim 14
Dependent Claim
23 words
An amplifier as defined in claim 10 wherein said first-named tuned circuit is series damped and said second tuned circuit is parallel damped.
Claim 15
Dependent Claim
19 words
An amplifier as defined in claim 10 wherein said first-named transistor and said second transistor are connected in cascade.
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) | 1975-12-19 | 1976-06-19 | 1976-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-19 | 1980-06-19 | 1980-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-19 | 1984-06-19 | 1984-12-19 | $7700.00 | Window Closed / Lapsed |