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一种适用于数字式VTR高密度录制的新型8—14通道编码已开发出来。在磁极跃过距离为2至7个通道比特且DSV(数字总磁差)的最大绝对值为7的条件下,利用此编码方法可将一个8位的数据词转换成一个14位的代码词。新开发的8—14位通道编码,其最小的录制波长和所需带宽分别比S—NRZ和M~2的长14% 和窄12.5%。此外,由于8—14通道编码是一种扫描宽度有限的分组编码,因此它有简化录放均衡、方位角和复写录制、无错传播及检谐等优点。由来自64比特率M—序列数据的8—14通道编码、S—NRZ编码和M~2编码进行编码的信号,在磁头磁带相对速度是21.4m/s、录放磁头磁迹宽度为20μm的情况下,可结合使用金属粒子磁带和铝硅铁层叠蒸镀式磁头进行录放。结果表明:8—14通道编码的重放信号,其SNR(信噪比)比S—NRZ和M~2编码的重放信号要高2.8dB。如今,8—14通道编码已被应用到D—3型VTR中。
A new 8-14 channel encoding for high-density digital VTR recording has been developed. With a magnetic pole jump distance of 2 to 7 channel bits and a maximum absolute value of DSV (Digital Total Magnetic Difference) of 7, an 8-bit data word can be converted into a 14-bit code word using this encoding method . The newly developed 8-14-bit channel encoding, the minimum recording wavelength and the required bandwidth were 14% longer and 12.5% narrower than S-NRZ and M ~ 2, respectively. In addition, since 8-14 channel encoding is a block-coded, limited-width scan, it simplifies recording and playback equalization, azimuth and re-writing, error-free propagation and detection. The signal encoded with 8-14 channel encoding, S-NRZ encoding and M-2 encoding from 64 bit rate M-sequence data was used when the head tape relative speed was 21.4 m / s and the recording and reproducing head track width was 20 μm , Can be combined with the use of metal particles tape and Al-Si stacked vapor deposition head for recording and playback. The results show that the SNR of signal reproduced by channel 8-14 is 2.8dB higher than that of S-NRZ and M ~ 2 encoded signals. Today, 8-14 channel encoding has been applied to the D-3 VTR.