Synchronous clock feedback circuit

Abstract

The invention discloses a synchronous clock feedback circuit, comprising a control module, a reference voltage module, a potentiometer module and a crystal oscillator module. The control module is used for simultaneously acquiring a calibration clock signal of an external atomic clock and a crystal oscillator clock signal of the crystal oscillator module, comparing the frequency of the calibrationclock signal and the crystal oscillator clock signal, and outputting a digital control signal if the frequency of the calibration clock signal and the crystal oscillator clock signal is different until the frequency of the calibration clock signal and the crystal oscillator clock signal is the same. The potentiometer module is used for adjusting a resistance value according to a digital control signal output by the control module to adjust an analog reference voltage output by the reference voltage module, and feeding back the adjusted analog reference voltage to the crystal oscillator module, thereby realizing the frequency stability calibration of the crystal oscillator module, which can achieve high frequency stability while avoiding the influence of the high cost, large volume and heavy weight of the atomic clock on an airborne radar system.

Description

technical field [0001] The invention relates to the technical field of clock circuits, in particular to a synchronous clock feedback circuit. Background technique [0002] Frequency stability is a key technical indicator of frequency source design. The frequency stability of the frequency source directly affects the demodulation of the radar receiver. The frequency stability of the frequency source is determined by the reference crystal oscillator. Therefore, how to achieve high frequency stability is a hot research topic in frequency source design. [0003] Currently, in order to achieve high frequency stability, such as figure 1 As shown, the existing clock circuit for achieving high frequency stability is to lock an atomic clock with high frequency stability to an internal crystal oscillator with relatively high short-term stability. [0004] Although the existing clock circuit for achieving high frequency stability can meet the system requirements in terms of technic...

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Problems solved by technology

[0004] Although the existing clock circuit for achieving high frequency stability can meet the system requirements in terms of technical indicators, factors such as high cost, large volume, and heavy module of the atomic clock cause difficulties in the engineering realization of the radar system, and it is difficult to meet the requirements of the airborne radar system. requirements

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