US3732497A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transistor transmitter using variable line length tuner
Assignee: VIDAR LABOR Inc
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Filing: 1971-02-10
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Granted: 1973-05-08
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Expires: 1991-02-10
Abstract
Abstract A transistor controlled transmitter whose modulation process occurs in the square law region by which is achieved extremely sensitive frequency modulation without the necessity of preamplifying stages for the modulating signal. A resonant circuit consists of an LC combination, the reactance of which is variable to change the oscillation frequency in the continuous mode. The variable reactance has physical dimensions which have been calculated to give a frequency of oscillation selectively over the FM band with maximum sensitivity and frequency stability. Other functions accomplished by the tuning means concomitant with the act of tuning include electromagnetic radiation of the modulated carrier wave with an essentially omnidirectional pattern, resonance of sufficient quality to smoothly adjust the frequency of oscillation, and control means having a unique position which obviates the need for a separate on-off switch.
Inventors
- 👤 J Campman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:29
CPC Classifications
H; H03; H03B; H03B5/00; H03B5/18; H03C; H03C3/00; H03C3/10; H03C3/12; H03C3/14; H03C3/145
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
365 words
A frequency modulated transmitter comprising, a unitary tunable resonant circuit means, switch and radiating member having, a strip of dielectric material having a substantial portion of its length from a first end toward the second end covered on opposite sides with a layer of electrically conductive material and a portion of its length at the second end uncovered by the layers of conductive material , a capacitor connected between the ends of said layers of conductive materialat the first end of said strip ; and a shorting means in contact with said layers of conductive material, slidably mounted on said strip from the first to the second ends thereof for shorting selectively different lengths of said layers for tuning the resonant circuit formed by said capacitor , the layers of conductive material and shorting means to different resonant frequencies, for opening the short between the conductive layers when said shorting means embraces the second end of said strip; an oscillator means for feeding energy to said resonant circuit means comprising , a transistor having a collector terminal connected to the end of one of said layers of conductive material at the first end of said strip , a base terminal and an emitter terminal, a feed-back circuit having a capacitor connected between said collector and emitter terminals , a biasing circuit comprising a resistor connected between said collector and base terminals , a second resistor having a first end connected to said emitter terminal and a source of direct current voltage connected between the second end of said second resistor and one of the ends of said layers of conductive material at the first end of said strip and through said shorting means and other layer of conductive material to the collector terminal , a radio frequency by-pass capacitor connected between said base terminal and the second end of said second resistor ; and an input means for modulating the frequency of said oscillator consisting of a pair of terminals , one connected to the base terminal of said transistor and the other connected to the second end of the second resistor whereby the modulating voltages are applied across the base-to-emitter junction of said transistor.
Claim 2
Dependent Claim
365 words
A frequency modulated transmitter comprising, a unitary tunable resonant circuit means, switch and radiating member having, a strip of dielectric material having a substantial portion of its length from a first end toward the second end covered on opposite sides with a layer of electrically conductive material and a portion of its length at the second end uncovered by the layers of conductive material , a capacitor connected between the ends of said layers of conductive materialat the first end of said strip ; and a shorting means in contact with said layers of conductive material, slidably mounted on said strip from the first to the second ends thereof for shorting selectively different lengths of said layers for tuning the resonant circuit formed by said capacitor , the layers of conductive material and shorting means to different resonant frequencies, for opening the short between the conductive layers when said shorting means embraces the second end of said strip; an oscillator means for feeding energy to said resonant circuit means comprising , a transistor having a collector terminal connected to the end of one of said layers of conductive material at the first end of said strip , a base terminal and an emitter terminal, a feed-back circuit having a capacitor connected between said collector and emitter terminals , a biasing circuit comprising a resistor connected between said collector and base terminals , a second resistor having a first end connected to said emitter terminal and a source of direct current voltage connected between the second end of said second resistor and one of the ends of said layers of conductive material at the first end of said strip and through said shorting means and other layer of conductive material to the collector terminal , a radio frequency by-pass capacitor connected between said base terminal and the second end of said second resistor ; and an input means for modulating the frequency of said oscillator consisting of a pair of terminals , one connected to the base terminal of said transistor and the other connected to the second end of the second resistor whereby the modulating voltages are applied across the base-to-emitter junction of said transistor.
Claim 3
Dependent Claim
46 words
The invention as defined in claim 1, wherein said shorting means is slidable from the covered to the uncovered portions of said strip of dielectric material for disconnecting the source of voltage from the collector terminal of said transistor to discontinue the operation of said transmitter.
Claim 4
Dependent Claim
96 words
The invention as defined in claim 2, wherein said layers of conductive material on said dielectric are arranged in parallel to each other to provide distributed inducTance and capacitance of the resonant circuit means , wherein the position of the shorting means on the covered portion of said strip determines the amount of inductive and capacitive reactance in the resonant circuit means and the resonant frequency thereof and wherein the portions of the layers of conductive material between the shorting means and the uncovered portion of said strip operates as the radiating member for the transmitter.
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) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |