A new 8-14 channel coding for D-3 format VTR

An 8-14 channel coding method suitable for high density recording for digital VTRs was developed. Using this coding, an 8-b data word is transformed into 14-b code word, assuming that the distance between magnetic polarity transitions is two to seven channel bits, the maximum absolute of the DSV (digital sum variation) is seven. The code has a minimum recorded wavelength 14% longer and a required bandwidth 12.5% narrower than those of S-NRZ and M² codes. Since it is a run-length-limited block code, it provides simplified recording and reproduction equalization, azimuth and overwrite recording, no error propagation to any other word, and error detection. The signals encoded by applying this method as well as S-NRZ and M² to 64-Mb/s M-sequence data were recorded and reproduced using metal particle tape and a Sendust laminated sputtered type head. The results show that the reproduced SNR of 8-14 channel coding was 2.8 dB higher than those of S-NRZ and M²