Frequency divider circuit and frequency synthesizer

Abstract

The invention relates to the field of circuit design, and discloses a frequency divider circuit and a frequency synthesizer, when the input end of an output unit is at a low level, the frequency divider circuit starts to work, and before the first rising edge of an initial clock signal arrives, the output unit outputs a high-level frequency division clock signal; after the first rising edge of the initial clock signal comes, the binary numbers corresponding to the M input ends of the output unit are equal to the frequency dividing ratio input N. Due to the action of the counting unit, every time the rising edge of the initial clock signal arrives, the binary numbers corresponding to the M input ends of the output unit can be subtracted by one, and the frequency dividing ratio input N is equal to the frequency dividing ratio input N. During the period, the frequency division clock signal is always at a low level, and the frequency division clock signal is changed into a high level again to enter the next period until the Nth rising edge of the initial clock signal comes, so that the period of the frequency division clock signal is N + 1 times of that of the initial clock signal, the purpose of frequency division of the initial clock signal is achieved, and the design process is simple.

Description

technical field [0001] The invention relates to the field of circuit design, in particular to a frequency divider circuit and a frequency synthesizer. Background technique [0002] In the field of integrated circuits, a frequency synthesizer is often used to multiply the frequency of the input signal. The frequency multiplication function of the frequency synthesizer needs to be realized through a frequency divider circuit and a feedback loop. The frequency divider circuit divides the output signal of the frequency synthesizer to generate Feedback signal, and then compare the feedback signal with the input signal of the frequency synthesizer, and make the frequency of the feedback signal equal to the frequency of the input signal of the frequency synthesizer through the feedback loop, and finally achieve the purpose of frequency multiplication of the input signal by the frequency synthesizer. It can be seen that The frequency divider circuit is very important. In the prior a...

AI Technical Summary

Problems solved by technology

[0002] In the field of integrated circuits, a frequency synthesizer is often used to multiply the frequency of the input signal. The frequency multiplication function of the frequency synthesizer needs to be realized through a frequency divider circuit and a feedback loop. The frequency divider circuit divides the output signal of the frequency synthesizer to generate Feedback signal, and then compare the feedback signal with the input signal of the frequency synthesizer, and make the frequency of the feedback signal equal to the frequency of the input signal of the frequency synthesizer through the feedback loop, and finally achieve the purpose of frequency multiplication of the input signal by the frequency synthesizer. It can be seen that The frequency divider circuit is very important. In the prior art, a digital frequency divider composed of pure digital circuits is often used. The design process needs to combine circuit design with coding, and the process is very complicated.

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