A Selection Method of Variable Fractional Sampling Rate

Abstract

The invention discloses a method for selecting a variable fractional multiple sampling rate. Firstly, the value range of the sampling rate and the conversion multiple of the sampling rate during anti-aliasing is obtained, and the value range is related to the repetition frequency of the output waveform. Then, according to DDWS The ratio of the maximum sampling rate of the waveform generator to the repetition frequency of the output waveform of the DDWS waveform generator, the cut-off frequency of the filter in the DDWS waveform generator and the maximum sampling rate of the DDWS waveform generator, the maximum frequency of the output waveform of the DDWS waveform generator and The relationship between the maximum sampling rate of the DDWS waveform generator, obtain the specific value of the sampling rate conversion multiple and obtain the sampling rate. On the premise of avoiding spectrum aliasing, it reduces the number of sampling rate points as much as possible, so as to reduce the hardware workload and required storage depth of the DDWS waveform generator. The sampling rate in the present invention can be changed along with the frequency of the output waveform, has a closer relationship with the output waveform, has stronger flexibility, and reduces the hardware workload of the instrument.

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 multiple 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 the traditional analog frequency synthesis technology, direct digital synthesis technology (DDS technology) is an all-digital frequency synthesis technology, because it has the advantages of high frequency resolution, fast conversion time, and low phase noise. , DDS technology has become the most widely used frequency synthesis technology. [0003] DDS technology adopts the structure of look-up table, and the waveform data stored in the look-up table is finally converted into the ideal target waveform through high-speed DAC. DDS-based waveform generation technolo...

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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