Dynamic magnetic information storage or retrieval – Modulating or demodulating
Patent
1989-12-15
1991-10-29
Canney, Vincent P.
Dynamic magnetic information storage or retrieval
Modulating or demodulating
360 46, G11B 2006, G11B 509
Patent
active
050620070
ABSTRACT:
A digital signal magnetic recording/reproducing apparatus converts a digital signal into a multi-value digital signal, followed by recording/reproducing the quadrature biphase modulated multi-value quadrature amplitude modulated signal. By using a multi-value quadrature amplitude modulation, a direct current component in the recorded signal can be eliminated, and the utilization efficiency of the recording frequency band of the digital signal magnetic recording/reproducing apparatus can be improved. Also, with respect to the amplitude non-linear characteristic which occurs in the magnetic recording/reproducing process, by providing a compensating circuit during the mapping before recording or after reproducing and demodulating, the deterioration of the S/N ratio of the reproduced and demodulated signal can be reduced to decrease the errors in the decoded data. Furthermore by bias-recording the multi-value quadrature amplitude modulation signal, the non-linearity of the electromagnetic conversion system is alleviated to decrease the deterioration of the S/N ratio due to distortion, thereby making the application of the modulation scheme more reliable.
REFERENCES:
patent: 4547817 (1985-10-01), Klaassen
"Signal System Design for a Digital Video Recording System"; L. Gallo; SMPTE J., 86:749-756, Oct. 1977.
"An Experimental Digital Video Recording System"; L.M.H.E. Dreissen et al.; IEEE Conf., Jun. 1986.
"An Experimental Digital VTR Capable of 12-Hour Recording"; C. Yamamitsu et al.; IEEE Trans. on CE, CE-33, No.3, pp. 240-248, 1987.
Kobayashi Masa-aki
Matsuta Toyohiko
Nakatsu Etsuto
Shimazaki Hiroaki
Shimotashiro Masafumi
Canney Vincent P.
Nissan Motor Company Limited
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