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US4804925A
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DPSK exclusive-OR demodulator
Assignee: Fujifilm Corp
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Filing: 1987-03-23
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Granted: 1989-02-14
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Expires: 2007-03-23
Abstract
Abstract A data signal is modulated by an exclusive-OR operation applied to a carrier signal and a data signal to be recorded. Demodulation is similarly performed by an exclusive-OR operation applied to the carrier signal and signal indicative of read data. This makes it possible to construct the modulating/demodulating circuit in the form of a digital circuit.
Inventors
- 👤 Yoshiki Iwase
- 👤 Katsuo Nakadai
- 👤 Izumi Miyake
- 👤 Kiyotaka Kaneko
- 👤 Kazuya Oda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:20
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/80; H04N9/82; H04N9/8205; H04N9/8211; H04N9/8222; G; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1403; G11B20/1407; G11B20/1419; H04N9/8233
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
107 words
A DPSK demodulating circuit comprising: a carrier signal generating circuit for generating a carrier signal for DPSK demodulation, and an exclusive-OR circuit to which are imputted a signal modulated by data and said carrier signal, said carrier signal generating circuit including: an edge sampling circuit for extracting both a leading and trailing edge of the modulated signal; a converting circuit for converting an output pulse signal from said edge sampling circuit into a rectangular signal having the same period of the output pulse signal and a duty factor of one-half; and a frequency dividing circuit for doubling the period of an output signal from said converting circuit.
Claim 2
Dependent Claim
107 words
A DPSK demodulating circuit comprising: a carrier signal generating circuit for generating a carrier signal for DPSK demodulation, and an exclusive-OR circuit to which are imputted a signal modulated by data and said carrier signal, said carrier signal generating circuit including: an edge sampling circuit for extracting both a leading and trailing edge of the modulated signal; a converting circuit for converting an output pulse signal from said edge sampling circuit into a rectangular signal having the same period of the output pulse signal and a duty factor of one-half; and a frequency dividing circuit for doubling the period of an output signal from said converting circuit.
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) | 1992-02-14 | 1992-08-15 | 1993-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-14 | 1996-08-15 | 1997-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-14 | 2000-08-15 | 2001-02-14 | $7700.00 | Window Closed / Lapsed |