The manner in order to suppress the emission of the electromagnetic interference in the digital system and

摘要

PROBLEM TO BE SOLVED: To digitally reduce an electromagnetic interference noise level by obtaining a first signal from a base signal by means of a digital system so as to execute modulation, obtaining a modulation reference signal which is fluctuated between an upper limit and a lower limit so as to generate a clock signal and diffusing the radiation of the electromagnetic interference noise of the clock signal. ;SOLUTION: Shortest transition corresponding to the base signal 13 is adopted as the active transition of the first signal 20 having a desired average frequency so that the first signal 20 is guided from the base signal 13 by the digital system. Then, modulation is executed in the frequency of the first signal 20 and the modulation reference signal 16 having the frequency which periodically fluctuates between the upper limit and the lower limit is obtained. Moreover, the clock signal is generated from the modulation reference signal 16. Then, the radiation of the electromagnetic interference noise of the modulation reference signal 16 is diffused over a first frequency band and the radiation of the electromagnetic interference noise of the clock signal is diffused over the second frequency band. Thus, the radiation of electromagnetic interference noise in the digital system is restricted.;COPYRIGHT: (C)1997,JPO