Dual-modulus prescaler using double edge triggered D-flip-flops

摘要

The present invention provides one dual-modulus prescaler using double edge triggered D-flip-flops. The dual-modulus prescaler comprises one double edge triggered synchronous block, one asynchronous block, and one combination logic block. The double edge triggered synchronous block is used to receive an input signal and a divisor selection signal from the combination logic block, and output a synchronous block output signal to the asynchronous block. The asynchronous block is used to receive the synchronous block output signal and output a plurality of signals to the combination logic block. One of the output signals of the asynchronous block is the output signal of the dual-modulus prescaler. The combination logic block is used to receive all the output signals of the asynchronous block and a modulus selection signal. Then, the combination logic block outputs the divisor selection signal and feeds it back to the double edge triggered synchronous block. The double edge triggered synchronous blockish composed of a plurality of D-flip-flops.