All-digital phase-locked loop system and frequency calibration method of all-digital phase-locked loop

Abstract

The invention discloses an all-digital phase-locked loop system and a frequency calibration method of the all-digital phase-locked loop, and the all-digital phase-locked loop system comprises: an all-digital phase-locked loop, which is used for correspondingly generating a first control code and a second control code when a corresponding loop is locked according to a carrier frequency signal and a crystal frequency signal in a calibration stage, and generating a target output frequency signal according to the crystal frequency signal and the second frequency amplification factor in a normal working stage; and a calibration unit, which is used for calibrating the first frequency amplification factor according to the first control code and the second control code to generate a second frequency amplification factor. According to the all-digital phase-locked loop system and the frequency calibration method of the all-digital phase-locked loop, the crystal frequency can be tracked, the frequency signal meeting the system requirement is output, and the risk that the accuracy of the frequency output by the all-digital phase-locked loop is reduced when a carrier wave is interfered or no carrier wave exists is reduced.

Description

technical field [0001] The invention relates to the technical field of electronic information, in particular to an all-digital phase-locked loop system and a frequency calibration method for the all-digital phase-locked loop. Background technique [0002] In the past ten years, the wireless radio frequency chip market has been booming, coupled with the continuous improvement of CMOS manufacturing technology, digital technology has played an increasingly important role in radio frequency chips. That is, more and more circuits will be realized by digital circuits. Because this can reduce the area of ​​the chip, reduce the cost, and can also enhance the configurability and process portability of the radio frequency chip. In the entire radio frequency chip, the phase-locked loop in the transceiver is the first to replace the original analog circuit with a digital circuit. Usually, in radio frequency applications, the accuracy of the output frequency of the phase-locked loop an...

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Problems solved by technology

But in some occasions, such as when the chip transmits a high-power signal, the carrier signal will be interfered, and in some occasions, there will be no carrier signal temporarily. These situations will cause the digital phase-locked loop to fail to provide the frequency required by the system. Signal

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