US4054840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
FM demodulator using multiplier to which delayed and undelayed input signals are applied
Assignee: Sony Corp
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Filing: 1976-09-08
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Granted: 1977-10-18
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Expires: 1996-09-08
Abstract
Abstract An FM signal demodulator including a multiplier having a pair of input terminals and an output terminal. A signal coupling circuit is connected between a circuit input terminal and one of the input terminals of the multiplier to couple an FM signal to the multiplier, and a delay line and a phase shifter are connected in cascade between the signal input terminal and the other input terminal of the multiplier. A low pass filter is connected to the output terminal of the multiplier to allow the demodulated signal to reach the circuit output terminal.
Inventors
- 👤 Teruo Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:06
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/02; H03D3/06; H03D3/22; H03D13/00; H03D13/007; H03D13/008; H03D2200/00; H03D2200/0001; H03D2200/0009; H03D2200/0041; H03D2200/0049
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
96 words
An FM demodulator comprising: a. a signal input terminal supplied with a frequency modulated signal; b. a multiplier having a pair of input terminals and an output terminal; c. a low pass filter connected to the output terminal of said multiplier to filter the output signal of the multiplier; d. coupling means for coupling said signal input terminal to one of said input terminals of said multiplier; and e. a series circuit comprising a delay line and a phase shifter connected between said signal input terminal and the other of the input terminals of said multiplier.
Claim 2
Dependent Claim
96 words
An FM demodulator comprising: a. a signal input terminal supplied with a frequency modulated signal; b. a multiplier having a pair of input terminals and an output terminal; c. a low pass filter connected to the output terminal of said multiplier to filter the output signal of the multiplier; d. coupling means for coupling said signal input terminal to one of said input terminals of said multiplier; and e. a series circuit comprising a delay line and a phase shifter connected between said signal input terminal and the other of the input terminals of said multiplier.
Claim 3
Dependent Claim
19 words
An FM demodulator according to claim 1, in which said delay line comprises an L-C type low pass filter.
Claim 4
Dependent Claim
18 words
An FM demodulator according to claim 1, in which said phase shifter comprises an all pass filter circuit.
Claim 5
Dependent Claim
92 words
An FM demodulator according to claim 3, in which said all pass filter comprises: a. a transistor having base, emitter and collector electrodes, the base being connected to the output of said delay line; b. a collector load resistor and an emitter load resistor connected to the collecter and emitter, respectively; and c. a second series circuit comprising a variable resistor and a capacitor connected between the collector and emitter electrodes of said transistor, the connection point between the variable resistor and capacitor comprising an output terminal of said all pass filter.
Claim 6
Dependent Claim
18 words
An FM demodulator according to claim 1, in which said multiplier comprises at least three cascade-connected differential amplifiers.
Claim 7
Dependent Claim
35 words
An FM demodulator according to claim 1, further including a buffer amplifier connected between said signal input terminal and the input side of said first-named series circuit comprising the delay line and the phase shifter.
Claim 8
Dependent Claim
33 words
An FM demodulator according to claim 6, further including a further buffer amplifier connected between the output side of said first-named series circuit and the other of said input terminals of said multiplier.
References Cited (Backward Citations)
US3387220A
Cited
US3701030A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-17 | 1981-04-18 | 1981-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-17 | 1985-04-18 | 1985-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-17 | 1989-04-18 | 1989-10-18 | $7700.00 | Window Closed / Lapsed |