Programmable frequency divider for expanding frequency dividing ratio

Abstract

The invention belongs to the technical field of frequency divider integrated circuits, and specifically relates to a programmable frequency divider for expanding a frequency dividing ratio. The programmable frequency divider comprises n cascaded 2 / 3 frequency dividing units, wherein the previous n-1 levels are 2 / 3 frequency dividing units without frequency dividing ratio expansion bits, the last level is a 2 / 3 frequency dividing unit having a frequency dividing ratio expansion bit; (the formula is as shown in the specification) is a frequency dividing ratio control bit, and the total frequencydividing range after the frequency dividing ratio is expanded is (formula is as shown in the specification); and the last level 2 / 3 frequency dividing unit having the frequency dividing ratio expansion bit adopts a latch with a reset end rst, and a time sequence conversion method is performed on the latch, so that the programmable frequency divider for expanding the frequency dividing ratio can work normally during the switch at the boundary of the frequency dividing ratio. Compared with the prior art, the programmable frequency divider overcomes the problem of frequency dividing ineffectiveness of the traditional programmable frequency divider during the switch at the boundary of the frequency dividing ratio, and has a simple structure and reliable performance; and the programmable frequency divider can be applied to broadband fractional part frequency dividing frequency synthesizer.

Description

technical field [0001] The invention belongs to the technical field of frequency divider integrated circuits, and in particular relates to a programmable frequency divider with extended frequency division ratio, which overcomes the problem of frequency division failure occurring when the classic frequency divider structure is switched at the boundary of the extended frequency division ratio, Can be used in wideband fractional frequency phase-locked loop. Background technique [0002] The frequency synthesizer is the core module of the radio frequency transceiver, and its performance directly determines whether the entire transceiver can work normally. The frequency synthesizer with fractional frequency division can obtain smaller frequency resolution when using a higher reference clock frequency and a wide loop bandwidth, and at the same time the dynamic characteristics and phase noise characteristics of the loop can be optimized. These advantages The frequency synthesizer ...

AI Technical Summary

Problems solved by technology

[0014] The purpose of the present invention is to provide a programmable frequency divider with extended frequency division ratio to overcome the frequency division failure problem when the frequency division ratio is switched at the boundary of the extended frequency division ratio

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