US3575661A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Remote control tuning circuit
Assignee: Motorola Solutions Inc
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Filing: 1968-11-05
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Granted: 1971-04-20
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Expires: 1988-11-05
Abstract
Abstract Remote control tuning of a television set is accomplished by providing a desired DC voltage level derived from an input signal at a particular frequency to a capacitor through a neon tube, and the voltage level stored in the capacitor is coupled to a varactor tuner by a field-effect transistor. In order to insure accurate tuning, the output of an automatic frequency control (AFC) circuit is added to the voltage present on the capacitor to modify the voltage level supplied to the field-effect transistor, thereby modifying the tuning voltage of the tuner causing it to pull on to the correct frequency.
Inventors
- 👤 William H Slavik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:04
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/02; H03J7/04; H03J7/08; H03J7/12
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
54 words
A control circuit according to claim 3 further including impedance means and wherein said other terminal of the capacitor is connected through the impedance means to a point of reference potential and the output of the frequency discriminator is coupled to the junction between said other terminal of the capacitor and the impedance means.
Claim 2
Dependent Claim
248 words
A tuner control circuit for a receiver having an RF tuner stage, an IF amplifier stage and an AFC discriminator connected to the IF amplifier stage, the tuner control circuit producing a DC output voltage indicative of the tuning frequency including in combination: a high impedance output circuit; capacitance means coupled to the high impedance output circuit; a source of DC tuning signals; a normally nonconductive voltage sensitive switching device coupled between the source of tuning signals and the capacitance means, said switching device being responsive to a potential thereacross in either direction greater than a predetermined magnitude to become conductive; means for applying the tuning signals to the switching device, tuning signals resulting in a potential across the switching device greater than said predetermined magnitude causing the switching device to become conductive to change the charge on the capacitance; and means for coupling the output of the AFC discriminator to the capacitance means to thereby modify the voltage supplied by the capacitance means to the high impedance output circuit. 6. A control circuit according to claim 5 wherein the RF tuner is a voltage-responsive tuner coupled to the high impedance output circuit. 7. A control circuit according to claim 5 wherein the voltage sensitive switching device is a neon tube and the high impedance output circuit is a field-effect transistor, with the capacitance means being connected at one terminal thereof to the junction between the output of the neon tube and the input to the field-effect transistor.
Claim 3
Dependent Claim
56 words
A control circuit according to claim 7 further including an impedance means and wherein the other terminal of the capacitance means is connected through the impedance means to a reference potential and wherein the output of the AFC discriminator is coupled to the junction between this other terminal of the capacitance means and the impedance means.
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) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |