[in Japanese]

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[in Japanese]

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This paper proposes a method of channel coding for parity check symbols in error-correcting codes. It applies the visual characteristics and coding rules of error-correcting codes, and suppresses the power of DC and low-frequency components Some errors in the least significant bit may be occurred by this channel coding, but the resultant degradation of image quality is too small to detect The power spectrum of image data is simulated, and it is confirmed that the method suppresses DC and low-frequency components. Furthermore, the channel coding without distortion can be achieved by means of a routine modification.

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We have developed an 8-14 channel coding suitable for high density recording for digital VTRs. Using this channel coding, which is a type of run length limited block code, 8-bit data is transferred to a 14-bit code, on the conditions that (1) the magnetic flux reversal length is from 2 to 7 clock intervals, and (2) the maximum absolute value of the DSV is 7. This newly-developed 8-14 channel coding has several merits, such as a narrow required frequency bandwidth, easy recording and reproduction equalizations, azimuth and overwrite recording, no error propagation to any other word, and error detection. This channel coding was applied to an NTSC composite digital VTR and a byte error rate of 7.5 x 10-6 has been obtained with a track width of 10 pm and a recorded wavelength of 0.76 pm, which corresponds to a recorded density of 3.3 pm2/bit.

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[in Japanese]

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