US4091241A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stereo indicating circuit for an FM receiver
Assignee: Trio KK
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Filing: 1976-12-15
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Granted: 1978-05-23
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Expires: 1996-12-15
Abstract
Abstract A stereo indicating circuit for use with an FM receiver having a multiplex demodulator, a stereo indicator and a stereo-monaural mode selector, the stereo indicating circuit comprising a smoothing circuit having a short time constant for changing the mode of the FM receiver from stereo to monaural and immediately turning off the stereo indicator after the power switch of the FM receiver is turned off by utilizing the sharp voltage drop of said smoothing circuit.
Inventors
- 👤 Kaku Sakaida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:00
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/1646; H04B1/1653
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
124 words
A stereo indicating circuit for use with an FM receiver comprising a multiplex demodulator responsive to a composite stereo signal; a stereo-monaural mode selector switch for switching said receiver to either the stereo or monaural mode of operation; a stereo indicator lamp which is lit when said receiver is in said stereo mode of operation and which is off when said receiver is in said monaural mode of operation; an AC power source; a first switch connected to said AC power source for de-energizing said receiver when said first switch is opened; and means responsive to said first switch being opened to place said receiver in its monaural mode of operation and thereby turn said stereo indicator lamp off when said receiver is de-energized.
Claim 2
Dependent Claim
124 words
A stereo indicating circuit for use with an FM receiver comprising a multiplex demodulator responsive to a composite stereo signal; a stereo-monaural mode selector switch for switching said receiver to either the stereo or monaural mode of operation; a stereo indicator lamp which is lit when said receiver is in said stereo mode of operation and which is off when said receiver is in said monaural mode of operation; an AC power source; a first switch connected to said AC power source for de-energizing said receiver when said first switch is opened; and means responsive to said first switch being opened to place said receiver in its monaural mode of operation and thereby turn said stereo indicator lamp off when said receiver is de-energized.
Claim 3
Dependent Claim
117 words
A stereo indicating circuit for use with an FM receiver comprising a multiplex demodulator responsive to a composite stereo signal; a stereo-monaural mode selector switch for switching said receiver to either the stereo or monaural mode of operation; a stereo indicator lamp for indicating when said receiver is in said stereo mode of operation; an AC power source; a first switch; a first smoothing circuit connected to said source of AC power by said first switch; and a voltage sensitive switch connected between said multiplex demodulator and said smoothing circuit for switching said receiver to said monaural mode of operation and turning said stereo indicator lamp off when said first switch is opened to de-energize said receiver.
Claim 4
Dependent Claim
117 words
A stereo indicating circuit for use with an FM receiver comprising a multiplex demodulator responsive to a composite stereo signal; a stereo-monaural mode selector switch for switching said receiver to either the stereo or monaural mode of operation; a stereo indicator lamp for indicating when said receiver is in said stereo mode of operation; an AC power source; a first switch; a first smoothing circuit connected to said source of AC power by said first switch; and a voltage sensitive switch connected between said multiplex demodulator and said smoothing circuit for switching said receiver to said monaural mode of operation and turning said stereo indicator lamp off when said first switch is opened to de-energize said receiver.
Claim 5
Dependent Claim
37 words
A circuit as in claim 2 including a further smoothing circuit for providing voltage for lighting said stereo indicator lamp, the time constant of said first smoothing circuit being shorter than that of said further smoothing circuit.
Claim 6
Dependent Claim
45 words
A circuit as in claim 3 where said voltage sensitive switch is a diode which is reverse biased when said first switch is closed and is immediately forward biased after said first switch is opened due to said shorter time constant of the smoothing 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) | 1981-05-22 | 1981-11-21 | 1982-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-22 | 1985-11-21 | 1986-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-22 | 1989-11-21 | 1990-05-23 | $7700.00 | Window Closed / Lapsed |