US3579115A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronically tuned oscillator
Assignee: Motorola Solutions Inc
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Filing: 1969-02-11
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Granted: 1971-05-18
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Expires: 1989-02-11
Abstract
Abstract An electronically tuned oscillator for use as a local oscillator in an AM radio receiver includes a transistor as the active component, with the emitter-base circuit of the transistor being supplied with signals obtained from two taps on the coil of the tank circuit of the oscillator. The tank circuit is tuned by use of a varactor or hyperabrupt diode supplied with tuning voltages obtained from a potentiometer connected across a DC source. The collector of the transistor is connected through a resistor to ground potential, and the taps are located to cause the reflected capacitance from the transistor across the tuning diode to be minimized, while at the same time providing sufficient energy to drive the transistor. The output of the transistor then is ACcoupled to a transistor amplifier stage which is AC-coupled to an emitter follower, the output of which supplies the oscillator signals to a mixer circuit in the radio receiver.
Inventors
- 👤 Nikolai Goncharoff
- 👤 Kamil Y Jabbar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:04
CPC Classifications
H; H03; H03J; H03J3/00; H03J3/02; H03J3/16; H03J3/18; H03J3/185; H03B; H03B5/00; H03B5/08; H03B5/12; H03B5/1206; H03B5/1221; H03B5/1231; H03B5/1237; H03B5/124; H03B5/1243; H03B2200/00; H03B2200/003; H03B2200/004; H03B2201/00; H03B2201/02; H03B2201/0208
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
108 words
In an electronically tuned AM radio receiver, an oscillator circuit including in combination: a transistor having collector, base, and emitter electrodes; a tank circuit, including a voltage variable capacitor as the tuning element therein, for controlling the oscillator frequency; means for connecting the tank circuit in the base-emitter circuit of the transistor; means for supplying a tuning voltage to the voltage variable capacitor; means for connecting the collector of the transistor to a constant DC load; means for isolating the output from the transistor and for supplying said output to the radio receiver; and means coupling the emitter of the transistor to the input of the isolating means.
Claim 2
Dependent Claim
108 words
In an electronically tuned AM radio receiver, an oscillator circuit including in combination: a transistor having collector, base, and emitter electrodes; a tank circuit, including a voltage variable capacitor as the tuning element therein, for controlling the oscillator frequency; means for connecting the tank circuit in the base-emitter circuit of the transistor; means for supplying a tuning voltage to the voltage variable capacitor; means for connecting the collector of the transistor to a constant DC load; means for isolating the output from the transistor and for supplying said output to the radio receiver; and means coupling the emitter of the transistor to the input of the isolating means.
Claim 3
Dependent Claim
21 words
The combination according to claim 1 wherein the constant load connected to the collector of the transistor is a fixed resistance.
Claim 4
Dependent Claim
24 words
The combination according to claim 2 wherein the fixed resistance is connected between the collector of the transistor and a source of reference potential.
Claim 5
Dependent Claim
42 words
The combination according to claim 1 wherein the voltage variable capacitor is a reverse-biased hyperabrupt diode device, the capacitance of which varies in accordanCe with the DC reverse bias voltage applied thereto, and the tuning voltage is a DC reverse bias voltage.
Claim 6
Dependent Claim
35 words
The combination according to claim 1 wherein the isolating means includes an AC-coupled amplifier supplying signals to an AC-coupled emitter follower, the output of which is supplied to a mixer circuit in the radio receiver.
Claim 7
Dependent Claim
19 words
The combination according to claim 5 wherein the amplifier and emitter follower are a transistor amplifier and emitter follower.
Claim 8
Dependent Claim
119 words
An electronically tuned AM radio receiver having a local oscillator including in combination: a transistor having base, emitter, and collector electrodes; a tank circuit for the oscillator including an inductor and a voltage variable tuning capacitor; means for supplying variable DC tuning voltage to the voltage variable capacitor in order to change the resonant frequency of the tank circuit, thereby changing the frequency of the output of the oscillator; means for connecting the emitter-base circuit of the transistor to the tank circuit; means for connecting the collector of the transistor to a constant DC load; and means for isolating and amplifying the output of the transistor and for supplying the isolated and amplified output to the radio receiver circuit.
Claim 9
Dependent Claim
119 words
An electronically tuned AM radio receiver having a local oscillator including in combination: a transistor having base, emitter, and collector electrodes; a tank circuit for the oscillator including an inductor and a voltage variable tuning capacitor; means for supplying variable DC tuning voltage to the voltage variable capacitor in order to change the resonant frequency of the tank circuit, thereby changing the frequency of the output of the oscillator; means for connecting the emitter-base circuit of the transistor to the tank circuit; means for connecting the collector of the transistor to a constant DC load; and means for isolating and amplifying the output of the transistor and for supplying the isolated and amplified output to the radio receiver circuit.
Claim 10
Dependent Claim
71 words
The combination according to claim 7 wherein the base of the transistor is connected to one tap on the inductor in the tank circuit and the emitter of the transistor is connected to another tap on the inductor of the tank circuit, the taps being located far enough apart in order to provide sufficient energy to drive the transistor while minimizing the reflected capacitance across the tank circuit from the transistor.
Claim 11
Dependent Claim
31 words
The combination according to claim 8 wherein the constant load connected to the collector of the transistor includes a resistor connected between the collector electrode and a source of reference potential.
Claim 12
Dependent Claim
51 words
The combination according to claim 9 wherein the isolating and amplifying means includes an AC-coupled transistor amplifier connected to the output of the first-mentioned transistor, with the output of the transistor amplifier being AC-coupled to an emitter-follower transistor, the output of which is supplied to a mixer in the radio receiver.
Claim 13
Dependent Claim
23 words
The combination according to claim 10 wherein the output of the first-mentioned oscillator transistor is AC-coupled from its emitter to the amplifier transistor.
References Cited (Backward Citations)
US3354397A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |