US3965302A
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US
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Stereo signal demodulator in a four-channel stereo broadcast receiver
Assignee: Sansui Electric Co Ltd
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Filing: 1975-01-28
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Granted: 1976-06-22
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Expires: 1995-01-28
Abstract
Abstract Improvements in a stereo signal demodulator of a receiver in a four-channel stereo system, in which system upon transmitting four sound source signals (LF, LB, RF and RB) from one station, the transmission is carried out for a synthesized signal composed of a signal in a main channel of (LF + LB) + (RF + RB), a pilot signal, a signal in a first sub-channel consisting of a double side-band signal obtained by modulating an m-multiple frequency-multiplied signal of the pilot signal with a signal of (LF + LB) - (RF + RB), a signal in a second sub-channel consisting of a double side-band signal obtained by modulating the same, m-multiple frequency-multiplied but phase-shifted signal with a signal of (LF - LB) + (RF - RB), and a signal in a third sub-channel consisting of a single side-band signal (SSB or VSB) obtained by modulating an n-multiple (m < n) frequency-multiplied signal of the pilot signal with a signal of (LF - LB) - (RF - RB). The four-channel stereo signal demodulator comprises a circuit for deriving from the pilot signal in said synthesized signal that has been FM-detected by a tuner an m-multiple frequency-multiplied signal of said pilot signal, a signal obtained by phase-shifting said m-multiple frequency-multiplied signal, and an n-multiple frequency-multiplied signal of said pilot signal; first, second and third switching circuits for switching their input signals consisting of said synthesized signal, respectively, under control of the respective three outputs of said signal deriving circuit to demodulate the signals in said respective channels from said synthesized signal; and a matrix circuit having the outputs of said three switching circuits applied to its input for separating and emitting at its output the signals LF, LB, RF and RB. The improvements reside in that a filter and a phase-compensator circuit are electrically coupled in the input circuit for the synthesized signal to said third switching circuit, and in that the outputs of said first and second switching circuits are applied to the input of the matrix circuit through the intermediary of respective delay lines.
Inventors
- 👤 Hirotaka Kurata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:15
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88; H04H20/89
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
320 words
A stereo signal demodulator for a receiver in a four-channel stereo system in which four sound source signals (Lf, LB, RF and RB) are transmitted from one station, the transmission being carried out for a synthesized signal comprising a signal in a main channel of (LF + LB) + (RF + RB), a pilot signal, a signal in a first sub-channel comprising a double side-band signal obtained by modulating an m-multiple frequency-multiplied signal of the pilot signal with a signal of (LF + LB) - (RF + RB), a signal in a second sub-channel comprising a double side-band signal obtained by modulating the same m-multiple frequency-multiplied but phase-shifted signal with a signal of (LF - LB) + (RF-RB), and a signal in a third sub-channel comprising a single side-band signal (SSB) obtained by modulating an n-multiple (m<n) frequency-multiplied signal of the pilot signal with a signal of (LF -LB) - (RF - RB); the four-channel stereo signal demodulator comprising: signal deriving circuit means including means for deriving from the pilot signal in said synthesized signal that has been FM-detected by a tuner an m-multiple frequency-multiplied signal of said pilot signal, a signal obtained by phase-shifting said m-multiple frequency-multiplied signal, and an n-multiple frequency-multiplied signal of said pilot signal; first, second and third switching circuits for switching their input signals comprised of said synthesized signal, respectively, under control of the respective three outputs of said signal deriving circuit means to demodulate the signals in said respective channels from said synthesized signal; a matrix circuit having the outputs of said three switching circuits applied to its inputs for separating and emitting at its output the signals LF, LB, RF and RB; a filter and a phase-compensator circuit coupling said synthesized signal to the input of said third switching circuit; and first and second delay means coupling the outputs of said first and second switching circuits to the inputs of said matrix circuit.
Claim 2
Dependent Claim
320 words
A stereo signal demodulator for a receiver in a four-channel stereo system in which four sound source signals (Lf, LB, RF and RB) are transmitted from one station, the transmission being carried out for a synthesized signal comprising a signal in a main channel of (LF + LB) + (RF + RB), a pilot signal, a signal in a first sub-channel comprising a double side-band signal obtained by modulating an m-multiple frequency-multiplied signal of the pilot signal with a signal of (LF + LB) - (RF + RB), a signal in a second sub-channel comprising a double side-band signal obtained by modulating the same m-multiple frequency-multiplied but phase-shifted signal with a signal of (LF - LB) + (RF-RB), and a signal in a third sub-channel comprising a single side-band signal (SSB) obtained by modulating an n-multiple (m<n) frequency-multiplied signal of the pilot signal with a signal of (LF -LB) - (RF - RB); the four-channel stereo signal demodulator comprising: signal deriving circuit means including means for deriving from the pilot signal in said synthesized signal that has been FM-detected by a tuner an m-multiple frequency-multiplied signal of said pilot signal, a signal obtained by phase-shifting said m-multiple frequency-multiplied signal, and an n-multiple frequency-multiplied signal of said pilot signal; first, second and third switching circuits for switching their input signals comprised of said synthesized signal, respectively, under control of the respective three outputs of said signal deriving circuit means to demodulate the signals in said respective channels from said synthesized signal; a matrix circuit having the outputs of said three switching circuits applied to its inputs for separating and emitting at its output the signals LF, LB, RF and RB; a filter and a phase-compensator circuit coupling said synthesized signal to the input of said third switching circuit; and first and second delay means coupling the outputs of said first and second switching circuits to the inputs of said matrix circuit.
Claim 3
Dependent Claim
25 words
A stereo signal demodulator according to claim 1 wherein said synthesized signal is coupled directly to the inputs of said first and second switching circuits.
Claim 4
Dependent Claim
28 words
A stereo signal demodulator according to claim 1 further comprising respective low pass filters coupling said first and second switching circuits to said first and second delay means.
Claim 5
Dependent Claim
20 words
A stereo signal demodulator according to claim 3 wherein said third switching circuit is coupled directly to said matrix circuit.
Claim 6
Dependent Claim
21 words
A stereo signal demodulator according to claim 1 including clock signal generator means coupled to said first and second delay means.
Claim 7
Dependent Claim
94 words
A stereo signal demodulator according to claim 1 wherein the inputs to said first switching means from said signal deriving circuit means are further coupled to said second delay means via respective ones of a first pair of delay means, and wherein the inputs to said second switching circuit from said signal deriving circuit means are coupled to said first delay means via respective ones of a second pair of delay means, the signals, supplied to said first and second delay means via said pairs of delay means serving as clock signal sources therefor.
Claim 8
Dependent Claim
38 words
A stereo signal demodulator according to claim 1 wherein the inputs to said third switching circuit from said signal deriving circuit means are applied to said first and second delay means to serve as clock signal sources therefor.
Claim 9
Dependent Claim
22 words
A stereo signal demodulator according to claim 1 wherein said n-multiple frequency-multiplied signal is twice the frequency of said m-multiple frequency-multiplied signal.
Claim 10
Dependent Claim
48 words
A stereo signal demodulator according to claim 8 wherein said m-multiple frequency-multiplied signal is a 38 kHz signal, said phase-shifted m-multiple frequency-multiplied signal is a signal of frequency 38 kHz at an angle of π/2, and wherein said n-multiple frequency-multiplied signal is a signal of frequency 76 kHz.
Claim 11
Dependent Claim
19 words
A stereo demodulator according to claim 1 wherein said first and second delay lines each comprise a charge-coupled device.
Claim 12
Dependent Claim
110 words
A stereo signal demodulator according to claim 10 wherein each of said first and second delay lines comprises a plurality of capacitor stages coupled in series with each other, each of said stages including a storage capacitor and means for transferring a charge on said storage capacitor to the storage capacitor of the next successive stage, every other stage being coupled to a first clock pulse terminal and every other remaining stage being coupled to a second clock pulse terminal, whereby successive clock pulses applied to said first and second terminals cause transfer of said charge from the capacitor of one stage to the capacitor of the next successive stage.
Claim 13
Dependent Claim
50 words
A stereo signal demodulator according to claim 11 further including a source of first and second clock pulses which are respectively coupled to said first and second clock pulse terminals of said respective first aand second delay means, said clock pulses being out of phase with each other by 180°.
Claim 14
Dependent Claim
323 words
A stereo signal demodulator for a receiver in a four-channel stereo system in which four sound source signaals (LF. LB, RF and RB) are transmitted from one station, the transmission being carried out for a synthesized signal comprising a signal in a main channel of (LF + LB) + (RF + RB), a pilot signal, a signal in a first sub-channel comprising a double side-band signal obtained by modulating an m-multiple frequency-multiplied signal of the pilot signal with a signal of (LF + LB) - (RF + RB), a signal in a second sub-channel comprising a double side-band signal obtained by modulating the same m-multiple frequency-multiplied but phase-shifted signal with a signal of (LF - LB) + (RF - RB), and a signal in a third sub-channel comprising a vestigial side-band signal (VSB) obtained by modulating an n-multiple (m<n) frequency-multiplied signal of the pilot signal with a signal of (LF - LB) - (RF - RB); the four-channel stereo signal demodulator comprising: signal deriving circuit means including means for deriving from the pilot signal in said synthesized signal that has been FM-detected by a tuner an m-multiple frequency-multiplied signal of said pilot signal, a signal obtained by phase-shifting said m-multiple frequency-multiplied signal, and an n-multiple frequency-multiplied signal of said pilot signal; first, second and third switching circuits for switching their input signals comprised of said synthesized signal, respectively, under control of the respective three outputs of said signal deriving circuit means to demodulate the signals in said respective channels from said synthesized signal; a matrix circuit having the outputs of said three switching circuits applied to its inputs for separating and emitting at its output the signals LF, LB, RF and RB; a filter and a phase-compensator circuit coupling said synthesized signal to the input of said third switching circuit; and first and second delay means coupling the outputs of said first and second switching circuits to the inputs of said matrix circuit.
Claim 15
Dependent Claim
323 words
A stereo signal demodulator for a receiver in a four-channel stereo system in which four sound source signaals (LF. LB, RF and RB) are transmitted from one station, the transmission being carried out for a synthesized signal comprising a signal in a main channel of (LF + LB) + (RF + RB), a pilot signal, a signal in a first sub-channel comprising a double side-band signal obtained by modulating an m-multiple frequency-multiplied signal of the pilot signal with a signal of (LF + LB) - (RF + RB), a signal in a second sub-channel comprising a double side-band signal obtained by modulating the same m-multiple frequency-multiplied but phase-shifted signal with a signal of (LF - LB) + (RF - RB), and a signal in a third sub-channel comprising a vestigial side-band signal (VSB) obtained by modulating an n-multiple (m<n) frequency-multiplied signal of the pilot signal with a signal of (LF - LB) - (RF - RB); the four-channel stereo signal demodulator comprising: signal deriving circuit means including means for deriving from the pilot signal in said synthesized signal that has been FM-detected by a tuner an m-multiple frequency-multiplied signal of said pilot signal, a signal obtained by phase-shifting said m-multiple frequency-multiplied signal, and an n-multiple frequency-multiplied signal of said pilot signal; first, second and third switching circuits for switching their input signals comprised of said synthesized signal, respectively, under control of the respective three outputs of said signal deriving circuit means to demodulate the signals in said respective channels from said synthesized signal; a matrix circuit having the outputs of said three switching circuits applied to its inputs for separating and emitting at its output the signals LF, LB, RF and RB; a filter and a phase-compensator circuit coupling said synthesized signal to the input of said third switching circuit; and first and second delay means coupling the outputs of said first and second switching circuits to the inputs of said matrix circuit.
Claim 16
Dependent Claim
25 words
A stereo signal demodulator according to claim 13 wherein said synthesized signal is coupled directly to the inputs of said first and second switching circuits.
Claim 17
Dependent Claim
28 words
A stereo signal demodulator according to claim 13 further comprising respective low pass filters coupling said first and second switching circuits to said first and second delay means.
Claim 18
Dependent Claim
20 words
A stereo signal demodulator according to claim 15 wherein said third switching circuit is coupled directly to said matrix circuit.
Claim 19
Dependent Claim
21 words
A stereo signal demodulator according to claim 13 including clock signal generator means coupled to said first and second delay means.
Claim 20
Dependent Claim
94 words
A stereo signal demodulator according to claim 13 wherein the inputs to said first switching means from said signal deriving circuit means are further coupled to said second delay means via respective ones of a first pair of delay means, and wherein the inputs to said second switching circuit from said signal deriving circuit means are coupled to said first delay means via respective ones of a second pair of delay means, the signals supplied to said first and second delay means via said pairs of delay means serving as clock signal sources therefor.
Claim 21
Dependent Claim
38 words
A stereo signal demodulator according to claim 13 wherein the inputs to said third switching circuit from said signal deriving circuit means are applied to said first and second delay means to serve as clock signal sources therefor.
Claim 22
Dependent Claim
22 words
A stereo signal demodulator according to claim 13 wherein said n-multiple frequency-multiplied signal is twice the frequency of said m-multiple frequency-multiplied signal.
Claim 23
Dependent Claim
48 words
A stereo signal demodulator according to claim 20 wherein said m-multiple frequency-multiplied signal is a 38 kHz signal, said phase-shifted m-multiple frequency-multiplied signal is a signal of frequency 38 kHz at an angle of π/2, and wherein said n-multiple frequency-multiplied signal is a signal of frequency 76 kHz.
Claim 24
Dependent Claim
20 words
A stereo signal demodulator according to claim 13 wherein said first and second delay lines each comprise a charge-coupled device.
Claim 25
Dependent Claim
110 words
A stereo signal demodulator according to claim 22 wherein each of said first and second delay lines comprises a plurality of capacitor stages coupled in series with each other, each of said stages including a storage capacitor and means for transferring a charge on said storage capacitor to the storage capacitor of the next successive stage, every other stage being coupled to a first clock pulse terminal and every other remaining stage being coupled to a second clock pulse terminal, whereby successive clock pulses applied to said first and second terminals cause transfer of said charge from the capacitor of one stage to the capacitor of the next successive stage.
Claim 26
Dependent Claim
50 words
A stereo signal demodulator according to claim 23 further including a source of first and second clock pulses which are respectively coupled to said first and second clock pule terminals of said respective first and second delay means, said clock pulses being out of phase with each other by 180°.
Claim 27
Dependent Claim
320 words
A stereo signal demodulator for a receiver in a four-channel stereo system in which four sound source signals (LF, LB, RF and RB) are transmitted from one station, the transmission being carried out for a synthesized signal comprising a signal in a main channel of (LF + LB) + (RF + RB), a pilot signal, a signal in a first sub-channel comprising a double side-band signal obtained by modulating an m-multiple frequency-multiplied signal of the pilot signal with a signal of (LF + LB) - (RF + RB), a signal in a second sub-channel comprising a double side-band signal obtained by moulating the same m-multiple frequency-multiplied but phase-shifted signal with a signal of (LF - LB) + (RF - RB), and a signal in a third sub-channel comprising a signal obtained by modulating an n-multiple (m<n) frequency-multiplied signal of the pilot signal with a signal of (LF - LB) - (RF - RB); the four-channel stereo signal demodulator comprising: signal deriving circuit means including means for deriving from the pilot signal in said synthesized signal that has been FM-detected by a tuner an m-multiple frequency-multiplied signal of said pilot signal, a signal obtained by phase-shifting said m-multiple frequency-multiplied signal, and an n-multiple frequency-multiplied signal of said pilot signal; first, second and third switching circuits for switching their input signals comprised of said synthesized signal, respectively, under control of the respective three outputs of said signal deriving circuit means to demodulate the signals in said respective channels from said synthesized signal; a matrix circuit having the outputs of said three switching circuits applied to its inputs for separating and emitting at its output the signals LF, LB, RF and RB; a filter and a phase-compensator circuit coupling said synthesized signal to the input of said third switching circuit; and first and second delay means coupling the outputs of said first and second switching circuits to the inputs of said matrix circuit.
Claim 28
Dependent Claim
320 words
A stereo signal demodulator for a receiver in a four-channel stereo system in which four sound source signals (LF, LB, RF and RB) are transmitted from one station, the transmission being carried out for a synthesized signal comprising a signal in a main channel of (LF + LB) + (RF + RB), a pilot signal, a signal in a first sub-channel comprising a double side-band signal obtained by modulating an m-multiple frequency-multiplied signal of the pilot signal with a signal of (LF + LB) - (RF + RB), a signal in a second sub-channel comprising a double side-band signal obtained by moulating the same m-multiple frequency-multiplied but phase-shifted signal with a signal of (LF - LB) + (RF - RB), and a signal in a third sub-channel comprising a signal obtained by modulating an n-multiple (m<n) frequency-multiplied signal of the pilot signal with a signal of (LF - LB) - (RF - RB); the four-channel stereo signal demodulator comprising: signal deriving circuit means including means for deriving from the pilot signal in said synthesized signal that has been FM-detected by a tuner an m-multiple frequency-multiplied signal of said pilot signal, a signal obtained by phase-shifting said m-multiple frequency-multiplied signal, and an n-multiple frequency-multiplied signal of said pilot signal; first, second and third switching circuits for switching their input signals comprised of said synthesized signal, respectively, under control of the respective three outputs of said signal deriving circuit means to demodulate the signals in said respective channels from said synthesized signal; a matrix circuit having the outputs of said three switching circuits applied to its inputs for separating and emitting at its output the signals LF, LB, RF and RB; a filter and a phase-compensator circuit coupling said synthesized signal to the input of said third switching circuit; and first and second delay means coupling the outputs of said first and second switching circuits to the inputs of said matrix circuit.
Claim 29
Dependent Claim
94 words
A stereo signal demodulator according to claim 25 wherein the inputs to said first switching means from said signal deriving circuit means are further coupled to said second delay means via respective ones of a first pair of delay means, and wherein the inputs to said second switching circuit from said signal deriving circuit means are coupled to said first delay means via respective ones of a second pair of delay means, the signals supplied to said first and second delay means via said pairs of delay means serving as clock signal sources therefor.
Claim 30
Dependent Claim
22 words
A stereo signal demodulator according to claim 25 wherein said n-multiple frequency-multiplied signal is twice the frequency of said m-multiple frequency-multiplied signal.
Claim 31
Dependent Claim
48 words
A stereo signal demodulator according to claim 27 wherein said m-multiple frequency-multiplied signal is a 38 kHz signal, said phase-shifted m-multiple frequency-multiplied signal is a signal of frequency 38 kHz at an angle of π/2, and wherein said n-multiple frequency-multiplied signal is a signal of frequency 76 kHz.
Claim 32
Dependent Claim
20 words
A stereo signal demodulator according to claim 25 wherein said first and second delay lines each comprise a charge-coupled device.
Claim 33
Dependent Claim
110 words
A stereo signal demodulator according to claim 29 wherein each of said first and second delay lines comprises a plurality of capacitor stages coupled in series with each other, each of said stages including a storage capacitor and means for transferring a charge on said storage capacitor to the storage capacitor of the next successive stage, every other stage being coupled to a first clock pulse terminal and every other remaining stage being coupled to a second clock pulse terminal, whereby successive clock pulses applied to said first and second terminals cause transfer of said charge from the capacitor of one stage to the capacitor of the next successive stage.
Claim 34
Dependent Claim
50 words
A stereo signal demodulator according to claim 30 further including a source of first and second clock pulses which are respectively coupled to said first and second clock pulse terminals of said respective first and second delay means, said clock pulses being out of phase with each other by 180°.
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) | 1979-06-22 | 1979-12-22 | 1980-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-22 | 1983-12-22 | 1984-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-22 | 1987-12-22 | 1988-06-22 | $7700.00 | Window Closed / Lapsed |