A Wideband Programmable Frequency Divider and A Frequency Synthesizer including the same

摘要

PURPOSE: A broadband variable frequency divider and a frequency synthesizer including the same are provided to eliminate an offset caused by an SR(Set Reset) latch in a dividing ratio by using an output of a B counter which is a kind of a swallow counter. CONSTITUTION: A dual modulus prescaler(700) controls input signals according to a control signal MC(Modulus Control). An A counter(702) performs a down-counting of the output signal of the dual modulus prescaler. A B counter(704) performs a down-counting of the output signal of the dual modulus prescaler for a dividing ratio switch timing of the dual modulus prescaler. A D-flip flop(710) outputs the control signal MC for controlling the dividing ratio of the dual modulus prescaler by inputting the output signal of the B counter.