High-efficiency measurement method for sinusoidal signal frequency in undersampling and implementation device

Abstract

The invention belongs to the technical field of digital signal processing, and provides a high-efficiency measurement method of a sinusoidal signal frequency in undersampling and an implementation device which can estimate parameters such as frequency and the like under the condition of undersampling and can finish precise frequency measurement. The invention adopts the technical scheme that traditional FFT spectrum analysis and all phase FFT spectrum analysis are adopted to obtain a peak value spectrum G (q) and a peak value spectrum Ga (q); a phase value is directly read from the peak valuespectrum to take the square of a G (q) modulus to obtain a power spectrum value Pg (q); after performing modulus division on Pg (q) and Ga (q), amplitude estimation is obtained to take the differenceof the phase value of G (q) and the phase value of g(q), and the difference divided by tau=(N-1) / 2 to obtain frequency offset estimation delta k; and finally delta k delta omega and q delta omega aresuperposed to obtain digital angular frequency estimation which directly serves as the phase estimation and the amplitude estimation of the measured signal. The invention is mainly used for undersampling measurement in digital signal processing.

Description

technical field [0001] The invention belongs to the technical field of digital signal processing. Specifically related to a new method for estimating the frequency of a sinusoidal wave with high accuracy and its corresponding experimental setup when the sampling rate is insufficient (compared to the signal frequency), i.e. an efficient measurement method and implementation of the frequency of a sinusoidal signal under undersampling device. Background technique [0002] In engineering fields such as communications, instrumentation, electric power, optical applications, and fault diagnosis, there are a large number of high-precision, efficient, and fast estimation problems for the frequency and phase of high-frequency sine waves. For example, coherent demodulation is the most common demodulation method in communication [1]. Coherent demodulation requires the receiver to extract information from the received signal and generate a local carrier with the same frequency and phase...

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Problems solved by technology

[0007] The disadvantages of this method are: (1) The pulse count signal needs to be specially generated, and the measurement accuracy largely depends on the basic pulse width T 0 , only by reducing T 0 In order to improve the measurement accuracy and expand the measurement range of the instrument, this has high requirements for hardware equipment; (2) only single-frequency signals can be measured and estimated; (3) the reference sine wave needs to be generated to complete the phase counting, and the reference signal and The frequency of the measured sinusoidal signal is exactly the same, if there is a slight deviation, it will bring serious deviation to the measurement result

[0016] However, it has been proved by experiments and theory that these phase estimation methods based on FFT spectrum correction have the following defects: (1) FFT has spectral leakage phenomenon. It affects the measurement accuracy of the phase to a great extent; (2) Due to the spectral leakage, these correction methods are not suitable for phase estimation occasions with dense spectrum [18]; (3) It is found through investigation that these FFT spectrum correction methods are not effective in estimating For the phase, the frequency is estimated first, and then the phase estimation is performed after obtaining the frequency deviation value. Therefore, a direct impact of this is that the error of the frequency estimation will be brought into the phase estimation.

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