JPS54112152A - Frequency divider - Google Patents

Abstract

PURPOSE:To obtain a frequency of a dividing ratio, which is not an integer, by providing three divider, a change-over circuit, and an inverter circuit and by setting ratios of respective dividers to values obtained by dividing one by adequate integers. CONSTITUTION:Clock input signal (fmu) of frequency (fmu) is applied to both divider 1 dividing a signal by M and divider 2 dividing a signal by N (M and N are integers). Output signals XA and XB of dividers 1 and 2 are supplied to divider 3, which divides signals XA and XB by K (K is an integer), via change-over circuit 5 to obtain output signal XC. Signal XC is sent out as a gate signal to divider 2 and switching signal GB of circuit 5 and signal XC is also passed through inverter circuit 6 to be supplied as gate signal GA of divider 1. As a result, the relation of the ratio between the frequency of output signal (ft) and that of input signal (fmu) is shown by equation (1), and when N is made equal to M+1, equation (3) is obtained, so that a frequency with a dividing ratio can be obtained which damps below a decimal point.