METHOD AND DEVICE FOR GENERATING CLOCK SIGNAL PROVIDED WITH FREQUENCY EQUIVALENT TO OSCILLATOR FREQUENCY OBTAINED THROUGH SUBTRACTION IN DECIMAL PART

摘要

PROBLEM TO BE SOLVED: To generate the pulse of a frequency having a fractional value by generating a pulse clock signal, permitting its periodic pulses to be provided with an oscillator frequency and permitting the pulse clock signal to be provided with an average frequency which is equal to the oscillator frequency which is subtracted or divided by means of a fraction having a numerator and a denominator. SOLUTION: A 32 MHz oscillator clock signal input 12 is subtracted by 50/9 and a counting circuit 18 having 50 states is used in a circuit 10 for generating a 5.76 MHz clock signal. One pulse in 9 pulses is generated among the entire fifty 32 MHz pulses of the signal input 12, so that the 5.76 MHz clock signal 42 is generated. The counting circuit 18 consists of the first counting element 20 of a four-bit pseudo-random counter and a counting element 30 of a six-bit shift register and the average frequency, which is asserted to the bit of the counting element 30 by the logical operations of the both counting elements is made equal to the frequency of the periodic pulse 12 which is divided fractionally.