GPS (Global Positioning System) synchronizing signal frequency source circuit

Abstract

The invention provides a GPS (Global Positioning system) synchronizing signal frequency source circuit. The GPS synchronizing signal frequency source circuit at least comprises the following signal synchronization processing modules: a GPS counting signal generator, a crystal oscillation clock signal counter, an average clock period processor and a synchronous clock signal generator. The GPS synchronizing signal frequency source circuit is characterized in that the GPS counting signal generator performs frequency division on a crystal oscillation signal by taking a GPS pulse per second as a trigger signal; the crystal oscillation clock signal counter is used for receiving the crystal oscillation clock signal, and calculating an average frequency error of the crystal oscillation clock signal through average clock period processing; and the synchronous clock signal generator is used for generating a frequency signal which is synchronous to the GPS pulse per second and correcting a crystal oscillation frequency error in order to output a frequency division frequency signal which is synchronous to the GPS pulse per second. Through adoption of the GPS synchronizing signal frequency source circuit, the problems that a crystal oscillation frequency signal cannot be synchronous to the GPS pulse per second and an output alternating-current signal is distorted in an existing throughput pulse method are solved, and a technical basis is laid for the realization of a time synchronization standard source.

Description

technical field [0001] The invention relates to the field of digital frequency synthesizers, in particular to a GPS synchronization signal frequency source circuit. Background technique [0002] Existing direct digital frequency synthesizers basically use a high-stable crystal oscillator as the frequency signal source. The high-stable crystal oscillator has the problem of frequency offset over time, and the output frequency signal is not synchronized with the GPS second pulse, so it cannot generate Frequency signal synchronized with GPS second pulse. [0003] In order to correct the frequency offset error of the high-stable crystal oscillator, the commonly used method is the throughput pulse method, that is, the error is evenly distributed into one clock cycle. For example, when the error is 20Hz and the crystal oscillator period is 100MHz, an extra count or One pulse cycle signal is undercounted. But this will lead to a very serious problem, that is, the clock cycle is un...

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Problems solved by technology

But this will lead to a very serious problem, that is, the clock cycle is uneven, and finally the waveform signal generated

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