PURPOSE: To obtain clocks of three kinds of sampling frequencies, 32, 44.1, 48kHz used for a digital audio equipment and clocks whose frequencles are a multiple of 256 of them by frequency-dividing variably the oscillation output of one original oscillator circuit.

CONSTITUTION: The generating circuit is featured to have an original oscillator circuit 2 generating an original clock whose frequency is 36.864MHz, a variable frequency divider circuit 3 frequency-dividing the original clock MCK, a frequency division number designation circuit 5 selecting the frequency division number of the variable frequency divider circuit 3 to be 1/3 when a sampling frequency 48kHz is obtained, selecting the frequency division number of the variable frequency divider circuit 3 to be 1/4.5 when a sampling frequency 32kHz is obtained, selecting the frequency division number of the variable frequency divider circuit 3 to be 1/3 for 47 times and to be 1/4 for 17 times so that the internal of 1/4 frequency division is almost an equal interval when a sampling frequency 44.1kHz is obtained, and a fixed frequency divider circuit 4 applying 1/256 frequency division to the output of the variable frequency divider circuit 3.