Digitized gapless phase noise measurement method based on group phase characteristic processing

Abstract

The invention discloses a digitized gapless phase noise measurement method based on group phase characteristic processing. The method comprises the following steps of: shaping a reference signal provided by a reference source into a rectangular pulse signal, carrying out frequency conversion on a signal to be measured and the rectangular pulse signal under the action of a controller, feeding the two signals which are subjected to the frequency conversion into a coincident point detection circuit together, and carrying out phase coincidence detection, wherein the phase shift processing is carried out on the rectangular pulse signal so as to accelerate a phase detection speed and accurately capture phase coincidence points; meanwhile, taking the phase coincidence points between the two signals as a measurement gate, and simultaneously starting up a counter to carry out gapless counting measurement on gate time, and reflecting the amplitude of phase noise by using the change of count values among the phase coincidence points; and finally, carrying out digital signal processing on time domain data which are measured when no gap gates exist, and displaying the single-sideband phase noise curve of the signal to be measured under the cooperation of a fast Fourier transform algorithm. The digitized gapless phase noise measurement method has the characteristics of simple circuit, high accuracy, capability of directly carrying out phase coincidence point detection on different-frequency signals, and the like.

Description

technical field [0001] The invention relates to a digital gapless phase noise measurement method based on group phase feature processing. Background technique [0002] With the rapid development of aerospace, navigation and positioning, deep space exploration, atomic frequency standards and other high-tech fields, high-precision frequency sources used for standard signals (such as time reference, communication carrier, etc.), especially for the phase of frequency sources The noise index puts forward higher requirements. Whether it is the transmitting excitation signal, the local oscillator signal of the receiver or various frequency references, the phase noise will appear in the demodulation terminal just like the useful signal in the demodulation process, which will reduce the baseband signal-to-noise ratio; in the communication system, the bit error will rate increase; affects target resolution in radar systems. Therefore, with the wide application of modern electronic s...

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Problems solved by technology

[0015] (2) The contradiction between fast response time and high resolution

Regardless of the same frequency or not, high-resolution phase coincidence detection methods are currently used in phase noise measurement. The higher the measurement resolution, the greater the error of the recovered coincidence information, the more difficult it is to detect the phase coincidence point, and the faster the gate opening speed. slow

[0016] (3) The problem of limited measurement accuracy

Digital phase noise measurement is limited by the AD sampling rate, and the phase noise measurement index is low, so it is not suitable for the measurement of high stability crystal oscillators

[0017] (4) Phase noise curve generation problem

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