Patent US4021756A successfully refreshed from Google Patents.
US4021756A
Expired / Lapsed
US
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Electric remote control transmitter
Assignee: Zenith Electronics LLC
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Filing: 1975-07-02
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Granted: 1977-05-03
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Expires: 1995-07-02
Abstract
Abstract An electronic remote control transmitter employs a two transistor cascade oscillator having positive and negative feedback loops. The oscillator voltage is supplied through a switch assembly containing a plurality of momentary contact switches to a pair of voltage dividers supplying signal voltages in predetermined ratios to a two branch circuit in the negative feedback loop. One branch contains an inductor and the second branch a capacitor. Closure of any switch completes the DC circuits for the transistors. Signal voltage is supplied to the branches to produce a minimum amplitude, zero phase shift condition which establishes oscillation at that predetermined frequency. The output of the oscillator is amplified by a third transistor and supplied to an ultrasonic transducer for generating acoustical control signals.
Inventors
- 👤 Robert R. Podowski
- 👤 Richard W. Citta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:39
CPC Classifications
H; H03; H03B; H03B5/00; H03B5/20; H03B5/24; B; B06; B06B; B06B2201/00; B06B2201/40; B06B2201/50; B06B2201/55; B06B2201/70
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
105 words
A transmitter for selectively generating a plurality of control signals of differing frequency for actuating a corresponding plurality of control functions in a remote receiver, comprising: an oscillator circuit including an amplifier with a positive feedback loop, and a negative feedback loop having an AC and a DC frequency determining branch and being capable of oscillation at several predetermined frequencies corresponding to said control signal frequencies dependent upon the ratio of signal voltages applied to said branches; and voltage dividing means coupled to said oscillator circuit and having a plurality of resistive elements for changing the ratio of said signal voltages applied to said branches.
Claim 2
Dependent Claim
105 words
A transmitter for selectively generating a plurality of control signals of differing frequency for actuating a corresponding plurality of control functions in a remote receiver, comprising: an oscillator circuit including an amplifier with a positive feedback loop, and a negative feedback loop having an AC and a DC frequency determining branch and being capable of oscillation at several predetermined frequencies corresponding to said control signal frequencies dependent upon the ratio of signal voltages applied to said branches; and voltage dividing means coupled to said oscillator circuit and having a plurality of resistive elements for changing the ratio of said signal voltages applied to said branches.
Claim 3
Dependent Claim
28 words
The transmitter of claim 1 further including means for maintaining a stable frequency in said oscillator by establishing the DC operating voltage levels independently of battery voltage variations.
Claim 4
Dependent Claim
53 words
The transmitter of claim 2 wherein said voltage dividing means comprises a plurality of serially connected resistors with taps at their junctions; and a plurality of single contact switches coupled between said taps and said oscillator circuit, closure of any of said switches forming two parallel voltage dividing networks across said oscillator circuit.
Claim 5
Dependent Claim
54 words
The transmitter of claim 3 wherein said first frequency determining branch comprises a high pass filter capacitor connected to a first tap of a first one of said voltage dividing networks, and said second frequency determining branch comprises a low pass filter inductor connected to a second tap of said second voltage dividing networks.
Claim 6
Dependent Claim
46 words
The transmitter of claim 4 wherein said oscillator circuit comprises a first and a second transistor in a cascade arrangement having a capacitor connected between the collector of said second transistor and the base of said first transistor providing said positive feedback loop for said oscillator.
Claim 7
Dependent Claim
45 words
The transmitter of claim 5 wherein the emitter of said second transistor is connected to said plurality of single contact switches; said inductor and said capacitor being connected together and to the base of said first transistor completing said negative feedback loop of said oscillator.
Claim 8
Dependent Claim
27 words
The transmitter of claim 6 wherein said means maintaining a stable frequency include a DC connection through said negative feedback loop and said cascade connection of transistor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-02 | 1980-11-01 | 1981-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-02 | 1984-11-01 | 1985-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-02 | 1988-11-01 | 1989-05-03 | $7700.00 | Window Closed / Lapsed |