Digital frequency demodulation phase noise measuring device and method

Abstract

The invention discloses a digital frequency demodulation phase noise measuring device and method and belongs to the electronic measurement technology field. A digital phase-locked loop is utilized torealize carrier frequency tracking and phase locking of a to-be-measured source, an intermediate frequency amplifying unit is utilized to realize adaptive adjustment, an original digital frequency demodulation unit is utilized to extract noise, and plural average of the frequency domain is utilized to improve the phase noise measurement sensitivity of a system. The method is advantaged in that when phase noise measurement can be realized through the frequency demodulation method, compatibility of frequency offset and sensitivity indexes is analyzed, and the better near-end phase noise measurement sensitivity can be realized; the realization scheme is simple, system configuration is concise, the technology is relatively mature, realization cost is low, and the cost performance advantage isrealized to a certain degree.

Description

technical field [0001] The invention belongs to the technical field of electronic measurement, and in particular relates to a digital frequency discrimination phase noise measurement device and method. Background technique [0002] Phase noise is an important index to measure the short-term frequency stability of a signal source, and it has an important impact on the performance of an electronic system. For example, in the radar T / R component, the phase noise of the local oscillator will affect the radar detection distance. In the communication system, the phase noise of the carrier will cause adjacent channel interference and demodulation errors. In the satellite navigation system, the phase of the uplink and downlink carriers Noise will affect the design cost and resource occupation of satellite payloads. The phase noise indicators of these electronic system signal sources are getting higher and higher. At the same time, in order to improve the target resolution and commun...

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Problems solved by technology

[0005] 1. When the power of the source to be measured is lower than the ideal power, the fixed IF gain will reduce the carrier power of the source to be measured after quantization compared with the noise power, thereby reducing the dynamic range of phase noise measurement; when the power of the source to be measured is higher than the ideal power When , the fixed IF gain may cause ADC saturation, resulting in wrong measurement results;

[0006] 2. Limited by the principle of frequency discrimination, the maximum analysis frequency deviation is proportional to the reciprocal of the delay time, and the sensitivity is proportional to the delay time. Therefore, for a single delay line, it is difficult to take into account the two indicators of frequency deviation and sensitivity analysis

The delay time of the analog delay line cannot be too long. The longer the delay line, the greater the attenuation, which will limit the improvement of sensitivity. Therefore, the frequency discrimination method usually achieves low sensitivity in close-carrier measurement.

[0007] 3. The signal source analyzer represented by FSUP will divide the horizontal axis analysis frequency deviation into several fixed segments, analyze and display segment by segment, the whole measurement time is longer and the efficiency is lower

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