US4506376A
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Subcarrier signal generator for use in stereo tuners
Assignee: Pioneer Corp
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Filing: 1982-12-16
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Granted: 1985-03-19
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Expires: 2002-12-16
Abstract
Abstract First and second rectangular signals which are 90° out of phase with each other are derived by comparators and an RS flip-flop from a symmetrical triangular wave signal. The first rectangular signal is halved in frequency by a frequency divider, the output of which is supplied to an adder. The second rectangular wave signal is also delivered to the adder. An output from the adder is converted by a bandpass filter into a sine-wave subcarrier signal in synchronism with a stereo pilot signal in an FM stereo tuner. The first and second rectangular signals may be derived by a pair of D-type flip-flops from a pulse signal.
Inventors
- 👤 Tadashi Noguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:08
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/1646; H04B1/1653; H03; H03D; H03D1/00; H03D1/22; H03D1/2209; H03D1/2236
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
190 words
A subcarrier signal generator for use in a stereo tuner, comprising: means for generating a symmetrical triangular wave signal in synchronism with a stereo pilot signal and having a fundamental of a frequency which is a multiple of a frequency of the stereo pilot signal, said triangular wave signal havng a highest level, a lowest level, and a midlevel between said highest and lowest levels; first means for generating a first rectangular wave signal by comparing said triangular wave signal with said midlevel thereof as a reference; second means for generating a second rectangular wave signal having a pulse width equal to a time interval between adjacent highest and lowest levels of said triangular wave signal; means for frequency-dividing said second rectangular wave signal to provide a frequency divided signal; level coincidence detector means responsive to said frequency divided signal and said first rectangular wave signal for generating an output; means for adding said frequency divided signal and said output from said level coincidence detector means at a certain level ratio; and means for extracting a fundamental component from an output of said adding means to produce a subcarrier signal.
Claim 2
Dependent Claim
190 words
A subcarrier signal generator for use in a stereo tuner, comprising: means for generating a symmetrical triangular wave signal in synchronism with a stereo pilot signal and having a fundamental of a frequency which is a multiple of a frequency of the stereo pilot signal, said triangular wave signal havng a highest level, a lowest level, and a midlevel between said highest and lowest levels; first means for generating a first rectangular wave signal by comparing said triangular wave signal with said midlevel thereof as a reference; second means for generating a second rectangular wave signal having a pulse width equal to a time interval between adjacent highest and lowest levels of said triangular wave signal; means for frequency-dividing said second rectangular wave signal to provide a frequency divided signal; level coincidence detector means responsive to said frequency divided signal and said first rectangular wave signal for generating an output; means for adding said frequency divided signal and said output from said level coincidence detector means at a certain level ratio; and means for extracting a fundamental component from an output of said adding means to produce a subcarrier signal.
Claim 3
Dependent Claim
33 words
A subcarrier signal generator according to claim 1, wherein said first means comprises a comparator having a reference level equal to said midlevel, for comparing said triangular wave signal with said reference level.
Claim 4
Dependent Claim
72 words
A subcarrier signal generator according to claim 1, wherein said second means comprises an upper-level comparator having a reference level equal to said highest level, a lower-level comparator having a reference level equal to said lowest level, and an RS flip-flop having a set input receptive of an output from said upper-level comparator, a reset input receptive of an output from said lower-level comparator, and an output connected to said frequency-dividing means.
Claim 5
Dependent Claim
15 words
A subcarrier signal generator according to claim 1, wherein said certain level ratio is (√2+1).
Claim 6
Dependent Claim
132 words
A subcarrier signal generator for use in a stereo tuner, comprising: means for generating two rectangular wave signals in synchronism with a stereo pilot signal, said rectangular wave signals being 90° out of phase with each other and having a fundamental of a frequency which is a multiple of a frequency of the pilot signal; means for frequency-dividing one of said rectangular wave signals to provide a frequency divided signal; level coincidence detector means responsive to said frequency divided signal and the other of said rectangular wave signals for generating an output; means for adding said frequency divided signal and said output from said level coincidence detector means at a certain level ratio; and means for extracting a fundamental component from an output of said adding means to produce a subcarrier signal.
Claim 7
Dependent Claim
132 words
A subcarrier signal generator for use in a stereo tuner, comprising: means for generating two rectangular wave signals in synchronism with a stereo pilot signal, said rectangular wave signals being 90° out of phase with each other and having a fundamental of a frequency which is a multiple of a frequency of the pilot signal; means for frequency-dividing one of said rectangular wave signals to provide a frequency divided signal; level coincidence detector means responsive to said frequency divided signal and the other of said rectangular wave signals for generating an output; means for adding said frequency divided signal and said output from said level coincidence detector means at a certain level ratio; and means for extracting a fundamental component from an output of said adding means to produce a subcarrier signal.
Claim 8
Dependent Claim
53 words
A subcarrier signal generator according to claim 5, wherein said generating means comprises a pair of D-type flip-flops each having a trigger input receptive of a trigger signal, and an output connected to a data input of the other flip-flop, one of the outputs of said flip-flops being connected to said frequency-dividing means.
Claim 9
Dependent Claim
15 words
A subcarrier signal generator according to claim 5, wherein said certain level ratio is (√2+1).
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) | 1988-03-18 | 1988-09-17 | 1989-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-18 | 1992-09-17 | 1993-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-18 | 1996-09-17 | 1997-03-19 | $7700.00 | Window Closed / Lapsed |