US3611155A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Search-tuning system sensitive to a dc voltage change
Assignee: Philips North America LLC
•
Filing: 1969-02-24
•
Granted: 1971-10-05
•
Expires: 1989-02-24
Abstract
Abstract The invention relates to a search-tuning system in which the coils of the relays which control the tuning motors are supplied with electrical energy via a flip-flop circuit. The flip-flop circuit is changed to its other condition to interrupt the supply of energy to the relay coils in response to the rise in DC voltage on the cathode of the FM quadrature demodulator tube in the sound system of the receiver. The circuit may be combined with an automatic turnoff circuit for turning the set off when there is no 4.5 MHz. sound I-F carrier being produced from the channel to which the turner is tuned.
Inventors
- 👤 Louis F Mayle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:54
CPC Classifications
H; H03; H03J; H03J1/00; H03J1/18; H03J1/20; H03J7/00; H03J7/18; H03J7/30
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
150 words
In a search tuning system for a television receiver having tuner means operated by tuning motors means and an audio system including sound demodulator means having a DC voltage which changes when a sound carrier is encountered; energizing circuit means for said motor means, relay means actuatable for completing said energizing circuit means and comprising coil means energizable for actuating said relay means, a source of voltage, a control circuit connecting one end of said coil means to said source of voltage, means for connecting the other end of said coil means to a point lower in potential than said source to energize said coil means, and control means including said control circuit operable in response to a change in said DC voltage present in said demodulator means for interrupting the supply of voltage from said source to said one end of said coil means to deenergize said coil means.
Claim 2
Dependent Claim
150 words
In a search tuning system for a television receiver having tuner means operated by tuning motors means and an audio system including sound demodulator means having a DC voltage which changes when a sound carrier is encountered; energizing circuit means for said motor means, relay means actuatable for completing said energizing circuit means and comprising coil means energizable for actuating said relay means, a source of voltage, a control circuit connecting one end of said coil means to said source of voltage, means for connecting the other end of said coil means to a point lower in potential than said source to energize said coil means, and control means including said control circuit operable in response to a change in said DC voltage present in said demodulator means for interrupting the supply of voltage from said source to said one end of said coil means to deenergize said coil means.
Claim 3
Dependent Claim
92 words
A search-tuning system according to claim 1 in which said control circuit comprises a first and normally conductive transistor having its collector-emitter path interposed between said source and said one end of said coil means, a second and normally nonconductive transistor connected to the base of said first transistor and operaBle when made conductive to bias said first transistor to cutoff, and said control means being connected to the base of said second transistor and biasing said second transistor to conduction in response to a rise in voltage in said demodulator means.
Claim 4
Dependent Claim
97 words
A search-tuning system according to claim 2 in which said control means comprises a third transistor having its collector-emitter path connected between a second source of voltage and ground and having its base connected to the DC voltage point in said demodulator means, a rise in voltage point of said demodulation means biasing said third transistor to conduction, and a connection from the collector-emitter path of said third transistor on the side nearest said second source to the base of said second transistor to bias said second transistor to conduction when said third transistor goes to conduction.
Claim 5
Dependent Claim
59 words
A search-tuning system according to claim 3 in which said receiver comprises an automatic shutoff system which includes an electrolytic capacitor connected to a third source so as to be charged thereby in the absence of a signal on a channel to which the receiver is tuned, said third transistor discharging said capacitor when said third transistor becomes conductive.
Claim 6
Dependent Claim
109 words
A search-tuning system according to claim 3, which includes components connecting both of the base and emitter of said third transistor to said DC voltage point of said demodulator means and holding said base and said emitter at the same potential under steady state voltage conditions of said DC voltage point whereby said third transistor is nonconductive under said steady-state condition, said components providing for a differential between the times the base and emitter of said third transistor reach the potential of said DC voltage point upon a rise in said voltage whereby said third transistor becomes conductive for a predetermined time only upon a rise in said voltage.
Claim 7
Dependent Claim
38 words
A search-tuning system according to claim 5 in which said components include resistance-capacitance combinations between said DC voltage point of said demodulator means and each of said base and emitter with the latter having the greatest time constant.
Claim 8
Dependent Claim
46 words
A search-tuning system according to claim 6, which includes a diode in parallel with the resistor of the network pertaining to the emitter of said third transistor to permit rapid discharging of the respective capacitance upon a drop in the voltage at said DC voltage point.
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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |