| 摘要 |
PURPOSE:To modulate and demodulate a digital signal which is suitable for write and readout of a magnetic recording device, by generating not only a binary signal of ''0'' and ''1'' but also a ternary signal by adding ''2'', and writing a signal expressed by ''2'' as a rectangular pulse at the time of write. CONSTITUTION:In a code conversion table, 8BX uses an 8 bit code, and 3 values of logic ''0'', ''1'' and ''2'', but logic 2 is used for a part (0001, 0110 and 1000 of 4B) marked with * in the margin. The conditions of this 8BX are as follows: (a) The last bit (bit of the right end) shall be always logic. (b) Between a bit of logic 1 and the following bit of logic 1, 2 or more bits of logic ''0'' are inserted. (c) 3 or more bits of logic ''0'' shall be always continued before and after the bit of logic 2. In this way, the 8BX is prepared. Therefore, a clock signal is extracted easily, and generation of a bit error can be prevented exactly. |
