| 摘要 |
PURPOSE:To send an auxiliary signal with a small circuit scale by applying pulse frequency modulation to an auxiliary signal input waveform and using the frequency modulation pulse so as to give 1B2B coding rule violation to a 1B2B code of a master signal. CONSTITUTION:An input waveform of an auxiliary signal inputted to an input terminal 6 is subjected to pulse frequency modulation by a modulation circuit 10 of the pulse frequency modulation system and a modulation pulse (a) is outputted. A retiming circuit 11 applies retiming to the modulation pulse (a) by a clock signal of a master signal and synchronizes it with the master signal and the result is fed to a CRV control input 13 of a coding circuit 1. In the presence of a modulation pulse (b), the coding circuit 1 applies CRV to the coding rule of the master signal. On the other hand, CRV is detected as soon as the master signal is decoded by a decoding circuit 2 at the reception side to obtain a waveform of a CRV detection signal (d) at a CRV detection output 14 and the signal (d) is used to demodulate the pulse frequency modulation at the demodulation circuit 12 thereby recovering the auxiliary signal waveform. |
