US3696301A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tuning indicating apparatus for fm receiver
Assignee: Nippon Gakki Co Ltd
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Filing: 1970-10-05
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Granted: 1972-10-03
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Expires: 1990-10-05
Abstract
Abstract In an FM receiver, a tuning indicating apparatus comprises a differential amplifier for receiving an FM detector output and delivering an output under a frequency-to-output response curve of a W-shape which is obtained by inverting one half of an Sshaped response curve of the FM detector; an AM detector connected to an IF amplifier; an AND circuit responsive to the outputs from the differential amplifier and the AM detector; and a tuning indicator energized by an output from the AND circuit.
Inventors
- 👤 Juro Hoshi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:15
CPC Classifications
H; H03; H03J; H03J3/00; H03J3/02; H03J3/12; H03J3/14; H03D; H03D3/00; H03D3/02; H03D3/06; H03D3/14
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
183 words
In an FM receiver including an RF tuner, an IF amplifier and an FM detector having an output and exhibiting an S-shaped frequency to voltage characteristic curve, tuning apparatus comprising a differential amplifier having an input connected to an output of the FM detector and another input free from an external signal, the differential amplifier having two outputs; an AM detector connected to the IF amplifier for detecting the receiving of a radio signal by the receiver, the AM detector having an output; an AND circuit having an input connected to an output of the differential amplifier, another input connected to another output of the differential amplifier, and still another input connected to an output of the AM detector, the differential amplifier and the AND circuit together producing a W-shaped frequency to voltage characteristic curve by inverting one half of the S-shaped characteristic curve of the FM detector thereby determining the zero point of the S-shaped curve as a peak point; and tuning indicating means energized by an output from the AND circuit and exhibiting a maximum indication when the receiver is tuned.
Claim 2
Dependent Claim
183 words
In an FM receiver including an RF tuner, an IF amplifier and an FM detector having an output and exhibiting an S-shaped frequency to voltage characteristic curve, tuning apparatus comprising a differential amplifier having an input connected to an output of the FM detector and another input free from an external signal, the differential amplifier having two outputs; an AM detector connected to the IF amplifier for detecting the receiving of a radio signal by the receiver, the AM detector having an output; an AND circuit having an input connected to an output of the differential amplifier, another input connected to another output of the differential amplifier, and still another input connected to an output of the AM detector, the differential amplifier and the AND circuit together producing a W-shaped frequency to voltage characteristic curve by inverting one half of the S-shaped characteristic curve of the FM detector thereby determining the zero point of the S-shaped curve as a peak point; and tuning indicating means energized by an output from the AND circuit and exhibiting a maximum indication when the receiver is tuned.
Claim 3
Dependent Claim
21 words
Tuning apparatus as claimed in claim 1, further comprising an amplifier connected between the AND circuit and the tuning indicating means.
Claim 4
Dependent Claim
99 words
Tuning apparatus as claimed in claim 1, wherein the differential amplifier comprises a pair of transistor amplifiers each having emitter, collector and base electrodes, a negative power source, a common resistor, a pair of base resistors, the emitter electrodes of the transistor amplifiers being connected to the negative power source via the common resistor, the base electrode of each of the transistors being connected to a point at ground potential via a corresponding one of the base resistors, the collector electrode of each of the transistors being connected to a corresponding one of the inputs of the AND circuit.
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) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |