US4507578A
Expired / Lapsed
US
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Frequency discriminating circuit
Assignee: Pioneer Corp
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Filing: 1982-06-17
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Granted: 1985-03-26
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Expires: 2002-06-17
Abstract
Abstract A frequency discriminating circuit is provided with multiple comparators corresponding in number to the number of frequencies to be discriminated, and the signal input to each comparator is also connected to each remaining comparator so as to raise the reference levels of the remaining comparators.
Inventors
- 👤 Khoichi Matsuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:10
CPC Classifications
H; H03; H03D; H03D3/00; H03J; H03J9/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
129 words
A frequency discriminating circuit for discriminating a plurality of signals of different frequency, comprising: a plurality of comparators provided according to said plurality of signals, said comparators respectively providing outputs when the levels of said signals are higher than respective reference levels; a common reference level setting circuit to establish an initial predetermined reference level input to said comparators; an input signal to any one of said plurality of comparators being used to increase the reference levels of the other comparators; and for each frequency to be discriminated, an active filter tuned to the respective frequency, and a rectifier coupled to the filter, an output of each rectifier being connected to a first input of a respective comparator, and being connected to a second input of the remaining comparators.
Claim 2
Dependent Claim
129 words
A frequency discriminating circuit for discriminating a plurality of signals of different frequency, comprising: a plurality of comparators provided according to said plurality of signals, said comparators respectively providing outputs when the levels of said signals are higher than respective reference levels; a common reference level setting circuit to establish an initial predetermined reference level input to said comparators; an input signal to any one of said plurality of comparators being used to increase the reference levels of the other comparators; and for each frequency to be discriminated, an active filter tuned to the respective frequency, and a rectifier coupled to the filter, an output of each rectifier being connected to a first input of a respective comparator, and being connected to a second input of the remaining comparators.
Claim 3
Dependent Claim
20 words
A circuit as claimed in claim 1, including reference level setting means connected to a second input of each comparator.
Claim 4
Dependent Claim
17 words
A circuit as claimed in claim 1, said second inputs of said comparators comprising reference level inputs.
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) | 1988-03-25 | 1988-09-24 | 1989-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-25 | 1992-09-24 | 1993-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-25 | 1996-09-24 | 1997-03-26 | $7700.00 | Window Closed / Lapsed |