Phase-locked loop type frequency synthesizer and radio frequency program-controlled frequency divider

Abstract

The invention provides a phase-locked loop type frequency synthesizer and a radio frequency program-controlled frequency divider, a phase-locked loop type frequency synthesizer comprising a reference oscillator, an R frequency divider, a phase discriminator, a charge pump, a loop filter, a voltage-controlled oscillator and a digital interface circuit, characterized in that a radio frequency input end of the radio frequency program-controlled frequency divider receives radio-frequency signals output by the voltage-controlled oscillator; an analog / digital control end receives code signals output by the digital interface circuit, and determines the frequency dividing ratio of the radio frequency program-controlled frequency divider by the code signals output by the digital interface circuit; the radio frequency program-controlled frequency divider performs frequency division on the received radio frequency signals and outputs to the phase discriminator, wherein the radio frequency program-controlled frequency divider comprises n 2 / 3 frequency dividing units, n is a natural number greater than or equal to 2, and all the 2 / 3 frequency dividing units adopt asynchronous series connection; and the synthesizer is characterized in that: each 2 / 3 frequency dividing unit is formed by a D-flip flop and a logic gate. The phase-locked loop type frequency synthesizer and radio frequency program-controlled frequency divider provided by the invention have simple system structures, low cost, small volumes, low power consumption, excellent performance, flexibility and convenience in use, and good application prospects.

Description

technical field [0001] The invention relates to a frequency synthesizer, in particular to a phase-locked loop frequency synthesizer and a radio frequency program-controlled frequency divider. Background technique [0002] The phase-locked loop frequency synthesizer is an important component widely used in wireless communication. It can be used as the local oscillator signal of various transceivers, and can also be used to complete functions such as modulation, demodulation and carrier recovery. The phase-locked loop frequency synthesizer contains high-frequency modules, low-frequency modules and digital circuits, and is a complex digital / analog / RF hybrid system. figure 1 Shown is an existing phase-locked loop frequency synthesizer system. The frequency characteristics of the system are usually limited by the high-frequency module - a programmable frequency divider. The programmable frequency divider usually uses a front-end dual-mode frequency divider, an M counter and an A ...

AI Technical Summary

Problems solved by technology

When the frequency division modulus value is from 8 / 9 to 64 / 65, the structure of the circuit becomes more and more complicated, and the time delay of the feedback signal becomes larger and larger. Therefore, as the whole phase-locked loop frequency synthesizer system As the operating frequency continues to increase, the operating current required by the dual-mode frequency divider will greatly increase, so there is a disadvantage of high power consumption

Moreover, when applied to the GHz radio frequency field, the frequency characteristics of the front-end dual-mode frequency divider are very high, and the operating current is usually increased to increase its operating frequency, resulting in a large overall system power consumption

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