High precision frequency measurement method and instrument at under-sampling rate

A frequency measurement, high-precision technology, applied in the direction of frequency measurement devices, instruments, special data processing applications, etc., to improve anti-noise performance, increase the range of measurement, and save hardware costs

Inactive Publication Date: 2014-08-27
TIANJIN UNIV
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Problems solved by technology

[0008] However, there is no literature to solve the frequency estimation problem of cosine signals under multi-channel undersampling. In the current academic and engineering circles, it is still a technical blank.

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  • High precision frequency measurement method and instrument at under-sampling rate

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Embodiment Construction

[0043] In order to make the purpose, technical solution and advantages of the present invention clearer, the implementation manners of the present invention will be further described in detail below.

[0044] The difficulty of frequency measurement for solving the frequency estimation problem of cosine signals under multi-channel under-sampling lies in that the cosine signal contains two complex exponential sidebands, so for a cosine signal of a certain frequency, FFT spectrum peak search is performed from L-channel low-speed sampling, It is inevitable to get 2L path remainders, how to select the effective L path remainders needed for CRT reconstruction from the 2L remainders is a very thorny problem. Embodiments of the present invention use phase information as the basis for screening to solve this problem, and combine the closed form of the Chinese remainder theorem to complete the frequency estimation of the cosine signal under sampling to fill the gap, see figure 1 , see t...

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Abstract

The invention discloses a high precision frequency measurement method and instrument at the under-sampling rate. The method includes the steps that spectrum correction is conducted through a triple-spectrum-line interpolation method, L pairs of frequency estimated values obtained after spectrum correction is obtained, and L pairs of phase information obtained after peak position correction is obtained; with the combination of the zero crossing point type and the L pairs of phase information obtained after correction, L frequency estimation values are picked out from the L pairs of frequency estimation values; all spectrum correction values and the L frequency estimation values are adopted as the remainder, and the frequency of an original high-frequency signal is reconstituted according to the Chinese remainder theorem in the closed analytical form. According to the measurement instrument, a single to be tested is subjected to the zero crossing point measurement processing firstly, and the original phase of the signal to be tested is determined; then sample sequences are obtained after analog / digital converter sampling with multi-path sampling frequency is conducted, the sample sequences enter a DSP device in the form of parallel digital input respectively, and frequency estimation of a high-frequency signal is obtained after internal processing is conducted through the DSP device; finally the frequency value is displayed with the help of an output driver and a display circuit of the output driver.

Description

technical field [0001] The present invention relates to the field of digital signal processing, in particular to a high-precision frequency measurement method at an under-sampling rate and its measuring instrument. The present invention relates to high-precision measurement of samples obtained from high-frequency cosine signals at multiple low-sampling rates . Background technique [0002] The high-precision frequency measuring instrument under the under-sampling rate has always been a difficult problem in the design of the frequency instrument. For example: for a 10MHz sine wave, it is difficult to measure the frequency at a sampling rate of several hundreds of kHz or even tens of kHz in the traditional frequency meter design. Because, in order to obtain the frequency information of the signal, according to the Nyquist sampling theorem, it is required to sample more than 2 sample points in one signal cycle at least, so the sampling rate must be higher than 20MHz. Sampling...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16G06F19/00G01R23/02
Inventor 黄翔东丁道贤孟天伟
Owner TIANJIN UNIV
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