Variable fractional sampling rate selection method

Abstract

The present invention discloses a variable fractional sampling rate selection method. The method comprises: obtaining the range of values of the sampling rate and the sampling rate conversion multiplewhen antialiasing, wherein the range of values is related to the repetition frequency of the output waveform; and according to the ratio of the maximum sampling rate of a DDWS waveform generator to the repetition frequency of the output waveform of the DDWS waveform generator, the relationship between the cutoff frequency of the filter in the DDWS waveform generator and the maximum sampling rateof the DDWS waveform generator, and the relationship between the highest frequency of the output waveform of the DDWS waveform generator and the maximum sampling rate of the DDWS waveform generator, obtaining the specific value of the sampling rate conversion multiple and obtaining the sampling rate. The sample rate points can be reduced as much as possible while avoiding spectrum aliasing, so that the DDWS waveform generator hardware workload and the required storage depth are reduced. The sampling rate in the present invention can be changed with the frequency of the output waveform, the relationship between the sampling rate and the output waveform is closer and more flexible, and the hardware workload of the instrument is reduced.

Description

Technical field [0001] The invention belongs to the technical field of arbitrary waveform generators, and more specifically, relates to a method for selecting a variable fractional sampling rate. Background technique [0002] With the rapid development of modern communication technology, the test system has higher and higher requirements for the accuracy and stability of the signal frequency. Compared with traditional analog frequency synthesis technology, direct digital synthesis technology (DDS technology) is an all-digital frequency synthesis technology, because of its high frequency resolution, fast conversion time, low phase noise, etc. , DDS technology has become the most widely used frequency synthesis technology. [0003] DDS technology adopts the structure of the look-up table, and the waveform data stored in the look-up table is finally converted into an ideal target waveform through a high-speed DAC. DDS-based waveform containing technology can be divided into two type...

AI Technical Summary

Problems solved by technology

In the actual sampling process, the method of selecting an integer multiple sampling rate is to convert the frequency of the output waveform to the sampling rate. The sampling rate can change with the frequency of different signals, but sometimes it cannot meet the requirements of avoiding spectrum aliasing and accuracy at the same time. Reconstruction signal requirements, so that the recovered waveform is seriously distorted; the method of selecting an arbitrary sampling rate is to convert the frequency of the sampling signal to a fixed sampling rate, this sampling rate is arbitrary and can be a fraction, but in order to To make the reconstructed signal close to the original signal, the number of sampling points required may be large, thus increasing the workload of the hardware

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