US3679979A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Am, fm, and fm stereo tuner having simplified am to fm switching means
Assignee: TARZIAN MARY
•
Filing: 1969-06-26
•
Granted: 1972-07-25
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Expires: 1989-06-26
Abstract
Abstract A tuner can be switched between AM, FM, and stereo modes of reception without any radio or audio-frequency band-switching, and without any changes being made in the tuning meter connections. Separate AM and FM radio sections have power terminals which are alternately connected to a source of power by a single pole, double throw AM or FM selector switch. The audio outputs of the two radio sections are fed into a mixing amplifier, and the mixing amplifier output is fed to stereo demodulation circuitry. A single tuning meter is connected between the FM section audio output and the AM section automatic gain control.
Inventors
- 👤 James Edgar Krepps Jr
- 👤 Meredith K Chamberlain
- 👤 Robert D Fisher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:56
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/005; H04B1/06; H04B1/16; H04B1/26; H04B1/38; H04B1/40; H04B1/403; H04B1/406
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
101 words
An AM and FM tuner comprising: an AM radio section having an AM audio output terminal, and also having an AM power terminal; an FM radio section having an FM audio output terminal, and also having an FM power terminal; a dual-input mixing amplifier having input terminals connected to both said AM and FM audio output terminals and having a single tuner audio output terminal; a source of power for said radio sections having a source of power terminal; and a switch for connecting said source of power terminal either to said AM power terminal or to said FM power terminal.
Claim 2
Dependent Claim
101 words
An AM and FM tuner comprising: an AM radio section having an AM audio output terminal, and also having an AM power terminal; an FM radio section having an FM audio output terminal, and also having an FM power terminal; a dual-input mixing amplifier having input terminals connected to both said AM and FM audio output terminals and having a single tuner audio output terminal; a source of power for said radio sections having a source of power terminal; and a switch for connecting said source of power terminal either to said AM power terminal or to said FM power terminal.
Claim 3
Dependent Claim
63 words
An AM and FM tuner in accordance with claim 1 wherein the AM radio section includes means for generating an automatic volume control signal, wherein the FM audio output includes a D.C. component that is proportional to the error in FM tuning, and which further includes a tuning meter connected to both the automatic volume control signal and to the FM audio output.
Claim 4
Dependent Claim
24 words
An AM and FM tuner in accordance with claim 1 wherein the dual-input mixing amplifier is an amplifier within a stereo multiplex demodulator circuit.
Claim 5
Dependent Claim
144 words
An AM and FM tuner comprising: an AM radio section including a tuning meter node at which appears a signal proportional to the AM signal strength; an FM radio section including an FM audio output node at which appears a signal proportional to the error in FM tuning; a tuning meter connected between said tuning meter node and said FM audio output node; and means for generating and for feeding to said tuning meter a zero shifting bias signal which biases said meter so as to shift the meter zero from the center of the scale to an edge of the scale when the FM reception is terminated and AM reception is commenced, and which biases the meter sufficiently to shift the meter zero from the edge of the scale back to center scale when AM reception is terminaTed and FM reception is commenced.
Claim 6
Dependent Claim
144 words
An AM and FM tuner comprising: an AM radio section including a tuning meter node at which appears a signal proportional to the AM signal strength; an FM radio section including an FM audio output node at which appears a signal proportional to the error in FM tuning; a tuning meter connected between said tuning meter node and said FM audio output node; and means for generating and for feeding to said tuning meter a zero shifting bias signal which biases said meter so as to shift the meter zero from the center of the scale to an edge of the scale when the FM reception is terminated and AM reception is commenced, and which biases the meter sufficiently to shift the meter zero from the edge of the scale back to center scale when AM reception is terminaTed and FM reception is commenced.
Claim 7
Dependent Claim
67 words
An AM and FM tuner in accordance with claim 4 wherein the signal proportional to the AM signal strength appears at the source electrode of a field effect transistor having its gate connected to a source of automatic volume control potential within the AM radio section, whereby the gate to source potential of the field effect transistor is a bias signal which shifts the tuning meter zero.
Claim 8
Dependent Claim
29 words
An AM and FM tuner in accordance with claim 5 wherein the field effect transistor also functions as a gain controlled radio frequency amplifier for the AM radio section.
References Cited (Backward Citations)
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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) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |