US4481548A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording and reproducing apparatus
Assignee: Olympus Corp
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Filing: 1983-09-09
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Granted: 1984-11-06
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Expires: 2003-09-09
Abstract
Abstract A still video signal is modulated to a PDM signal by a pulse duration modulator. The PDM signal is recorded by a perpendicular magnetic recording head on a recording medium of perpendicular magnetic anisotropy according to the perpendicular magnetic recording method. The PDM signal recorded on the recording medium is reproduced by a perpendicular magnetic reproducing head.
Inventors
- 👤 Tuneo Yanagida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:26
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/92; G; G11; G11B; G11B20/00; G11B20/02; G11B20/08; G11B20/22; G11B20/225
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
172 words
A magnetic recording and reproducing apparatus comprising: means for converting an analog input signal to a digital signal; means for pulse-duration-modulating said digital signal to produce an original pulse-duration-modulated signal, said original pulse-duration-modulated signal not being on a carrier signal; a magnetic recording head for recording said original carrierless pulse-duration-modulated signal on a recording medium of perpendicular magnetic anisotropy wherein said recording head perpendicularly magnetizes the recording medium in correspondence with said original pulse-duration-modulated signal; a reproducing head for reproducing the pulse-duration-modulated signal recorded on said recording mdium by said recording head; a differentiator coupled to said reproducing head for differentiating the pulse-duration-modulated signal reproduced by said reproducing head and for futher providing a differentiated signal having peak values; a peak value detector coupled to said differentiator for detecting the peak values of the differentiated signal from said differentiator and for generating a peak value signal; and means coupled to said peak value detector for modulating said peak value signal generated by said peak value detector to obtain the original pulse-duration-modulated signal.
Claim 2
Dependent Claim
172 words
A magnetic recording and reproducing apparatus comprising: means for converting an analog input signal to a digital signal; means for pulse-duration-modulating said digital signal to produce an original pulse-duration-modulated signal, said original pulse-duration-modulated signal not being on a carrier signal; a magnetic recording head for recording said original carrierless pulse-duration-modulated signal on a recording medium of perpendicular magnetic anisotropy wherein said recording head perpendicularly magnetizes the recording medium in correspondence with said original pulse-duration-modulated signal; a reproducing head for reproducing the pulse-duration-modulated signal recorded on said recording mdium by said recording head; a differentiator coupled to said reproducing head for differentiating the pulse-duration-modulated signal reproduced by said reproducing head and for futher providing a differentiated signal having peak values; a peak value detector coupled to said differentiator for detecting the peak values of the differentiated signal from said differentiator and for generating a peak value signal; and means coupled to said peak value detector for modulating said peak value signal generated by said peak value detector to obtain the original pulse-duration-modulated signal.
Claim 3
Dependent Claim
85 words
The magnetic recording and reproducing apparatus of claim 1 wherein said demodulating means comprises: a pulse generator for generating a pulse signal responsive to said peak value signals, said pulse signal having a pulse width corresponding to that of the original pulse-duration-modulated signal; a pulse train generator coupled to said pulse generator for generating a pulse train corresponding to the pulse width of the original pulse-duration-modulated signal; and means coupled to said pulse train generator for storing said pulse train of said pulse train generator.
Claim 4
Dependent Claim
30 words
The magnetic recording and reproducing apparatus of claim 1 which further includes correction means for removing an error signal contained in the pulse-duration-modulated signal as reproduced by said reproducing head.
Claim 5
Dependent Claim
17 words
The magnetic recording and reproducing apparatus of claim 1 wherein said reproducing head is a ring head.
Claim 6
Dependent Claim
74 words
The magnetic recording and reproducing apparatus of claim 1 wherein said demodulating means comprises: a pulse generator coupled to said peak value detector for generating a pulse signal in response to said peak values, said pulse signal having a pulse width corresponding to that of the original pulse-duration-modulated signal; and pulse train generating means coupled to said pulse generator for generating a pulse train corresponding to the pulse width of the original pulse-duration-modulated signal.
Claim 7
Dependent Claim
56 words
The magnetic recording and reproducing apparatus of claim 5, further comprising: a memory coupled to said pulse train generating means for storing said pulse train of said pulse train generating means; a source of a correction signal; and means for reading out said pulse train in response to said correction signal for correcting a reproducing error.
References Cited (Backward Citations)
US4390907A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-06 | 1988-05-07 | 1988-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-06 | 1992-05-07 | 1992-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-06 | 1996-05-07 | 1996-11-06 | $7700.00 | Window Closed / Lapsed |