CMI ENCODING CIRCUIT WITH CODE RULE ILLEGALITY

摘要

PURPOSE:To securely suppress the occurrence of a glitch by inputting the output signal of a CMI code to a decision circuit and comparing it with a data signal, etc., to be inputted next, and inputting a clock signal to a final-stage output inverting circuit only when it is necessary and inverting the output. CONSTITUTION:A decision circuit 1.6 compares a level which is outputted as a CMI code currently with an input data signal (NRZ code signal) from a latch delay circuit 1.4, an input CRV signal (code rule illegality signal of NRZ signal) from a latch circuit 1.5, and a level which are held by a data '1' level storage circuit 1.7, and outputs the next data signal and CRV signal after CMI encoding. In this case, when the level which is outputted currently needs to be inverted, one of gate circuits 1.8-1.10 is opened to output the clock signal to the output inverting circuit 1.11. The output inverting circuit 1.11 inverts the output at rises of clock signals from three input signal lines and outputs it as the signal of the CMI code.