Timing generator for plural reference clocks

Abstract

A timing generator compensates the difference between the reference clock frequencies by converting the base number for generating the timing signals corresponding to the ratio of reference clock frequencies. The timing generator includes: a data memory for dynamically receiving the timing data through the software process to determine the time length of the timing signals where the timing data is formed of a quotient produced by a division of the time length by a time period of a reference clock and a fraction which is a remainder of said division; a counter for counting the number of pulses of a reference clock signal and generating an output signal when the number of counts of the pulse coincides with the quotient; an accumulator for accumulating the fraction data with the fraction data of previous cycle of the reference clock signal and generating a carry signal when the accumulated value exceeds the time period of the reference clock signal; a number converter which converts the timing data provided through the software process based on a first reference clock period Tn by a ratio of the first reference clock period Tn and a second clock period Tm; and means for providing a complementary number -Tm of the second reference clock period Tm to the accumulator.