| 摘要 |
PURPOSE:To obtain an optimum transmission line code in an optical digital transmission by converting a pulse train at each m-bit into that at each (m+1)-bit and adding a 1-bit of parity bit so as to make the number of parity bits coincident with the number of '1' and '0' pulses of the converted pulse train. CONSTITUTION:The input digital signal is sectioned into pulse trains at each m-bit (m is an even number) and converted into a pulse train of (m+1)-bit according to a prescribed rule. In this case, the pulse train where the number of '1' pulses is (m+l)/2 or (m+1)/2-1 is selected in the rule of the pulse train to be converted. In case of the number of '1' pulses being (m+l)/2 with respect to the pulse train converted into (m+1)-bit, '0' is inserted to the parity bit, and in case of (m+1)/2-1 in the number of '1' pulses, '1' is inserted to the parity bit. Thus, a service data signal is sent easily by using a transmission line pulse train independently of the input pulse train. |
