US3701030A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fm demodulator circuit using phase-shifting multiplier
Assignee: Tokyo KK
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Filing: 1971-09-20
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Granted: 1972-10-24
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Expires: 1991-09-20
Abstract
Abstract An FM demodulator circuit in which is used a phase-shifting multiplier comprising a limiter for obtaining an output of a substantially rectangular waveform, a phase shifter for shifting the phase of the output of the limiter by 90*, a multiplier for producing the vector product of the output of the limiter and the output of the phase shifter, and a low-pass filter for obtaining a demodulated signal, is further improved by the provision of a waveform converter for converting the rectangular waveform into a substantially triangular waveform, between the limiter and the phase shifter, so that a reference signal for the multiplier is thereby made to assume a substantially triangular waveform.
Inventors
- 👤 Yukisato Gocho
- 👤 Takahiro Inokuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:47
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/02; H03D3/18
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
102 words
In an FM demodulating circuit of a phase-shifting and multiplying type comprising, a limiter for obtaining a substantially rectangular waveform output, a phase shifter for shifting the phase of the output of the limiter by 90*, a multiplier for producing the vector product of the output of the limiter and the output of the phase shifter, and a low-pass filter for producing a demodulated signal, the improvement comprising a waveform converter connected between the limiter and the phase shifter for converting the rectangular waveform into a substantially triangular waveform applied as a reference signal to the multiplier as a substantially triangular waveform.
Claim 2
Dependent Claim
102 words
In an FM demodulating circuit of a phase-shifting and multiplying type comprising, a limiter for obtaining a substantially rectangular waveform output, a phase shifter for shifting the phase of the output of the limiter by 90*, a multiplier for producing the vector product of the output of the limiter and the output of the phase shifter, and a low-pass filter for producing a demodulated signal, the improvement comprising a waveform converter connected between the limiter and the phase shifter for converting the rectangular waveform into a substantially triangular waveform applied as a reference signal to the multiplier as a substantially triangular waveform.
Claim 3
Dependent Claim
19 words
An FM demodulator circuit as set forth in claim 1 wherein the substantially triangular waveform includes a sinusoidal waveform.
Claim 4
Dependent Claim
26 words
An FM demodulator circuit as set forth in claim 1 wherein the multiplier is of a type having a switching time determined by the reference signal.
References Cited (Backward Citations)
US2922040A
Cited
US3351864A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |