Matching and harmonic suppression system and method based on navigation receiver clock link

Abstract

The invention relates to a matching and harmonic suppression system and method based on a navigation receiver clock link. The matching and harmonic suppression system comprises a TCXO, a level conversion circuit, a combined filter circuit, a clock buffer clock driving circuit, a radio frequency unit, an ADC and a signal processing end. A peak clipping sine wave is output through a TCXO, level conversion is carried out through a level conversion circuit, filtering is carried out through a combined filter circuit, a signal is adjusted to an LVCMOS level through a voltage regulation circuit, the signal is output to a clock buffer clock driving circuit, 10 paths of clock signals are output, the 10 paths of clock signals are respectively filtered and attenuated through the combined filter circuit, and 8 paths of clock signals are output to a radio frequency. One path of clock signal is output to a signal processing end, and a synchronous clock signal is output to a sampling ADC through a combined filter circuit so as to complete the processing of a clock link. According to the invention, the quality of the TCXO clock output signal is improved, and the harmonic wave of the local oscillator signal is reduced.

Description

technical field [0001] The invention relates to an impedance matching and harmonic suppression system and method of a clock signal in a transmission link of a clock source in a global satellite navigation system receiver, so as to improve the capture effect of the receiver. Background technique [0002] The current global satellite navigation system is developing rapidly, and Beidou-3 has successfully established a comprehensive network to help the development of global navigation and positioning systems. At present, the global satellite navigation system is mainly divided into four major satellites including Beidou (BDS), GPS, Galileo, and GLONASS Navigation System. At present, the positioning accuracy of high-precision satellite receiver boards is closely related to the quality of their clock signals. The on-board high-precision clocks mainly include TCXO (temperature-compensated crystal oscillator) and OCXO (constant temperature crystal oscillator). Although OCXO has high...

AI Technical Summary

Problems solved by technology

At present, the positioning accuracy of high-precision satellite receiver boards is closely related to the quality of their clock signals. On-board high-precision clocks mainly include TCXO (temperature-compensated crystal oscillator) and OCXO (constant temperature crystal oscillator). Although OCXO has higher precision, it is smaller in size. Large, it is difficult to integrate on the baseband board, so the TCXO crystal oscillator is commonly used at present

[0003] At present, the clock input requirements of RF and baseband chips are basically greater than 0.8Vpp, so in order to improve accuracy and reduce power consumption, the current TCXO output is mostly clipped sine wave (Clippedsin), and the output of peak clipped sine wave will increase the output harmonic At the same time, the duty cycle of the TCXO output is difficult to reach a perfect 50% due to the interference of the crystal oscillator manufacturer's production process and PCB design, so even harmonics will be generated. Combined with the above reasons, the 5th harmonic of the TCXO output The increase of energy in the wave will interfere with the baseband capture effect and ultimately affect the positioning accuracy. However, the clock source of the current high-precision positioning receiver lacks effective processing. Most of the clock links are connected to the clock receiving end through 10nF capacitors.

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