Low-rate end frequency estimation method of rapid convolution adjustable filer group

Abstract

The invention belongs to the field of digital signal processing, and provides a low-rate end frequency estimation method of a rapid convolution adjustable filer group, for realizing the purposes of determining relative positions between an output frequency spectrum and an input frequency on a corresponding filter passband, estimating the frequency of high-rate input signals at a low-rate end, and substantially inhibiting an error diffusion effect. The technical scheme employed by the invention is as follows: the low-rate end frequency estimation method of the rapid convolution adjustable filer group is divided into the following two phases: 1, a rapid convolution phase: step 1, performing overlapping segmentation on input signals x(n); step 2, performing N-point fast Fourier transform (FFT) on each segment; step 3, observing FFT amplitude output corresponding to each sub-band; step 4, performing Lk-point inverse FFT on a result after the sub-band is weighed; and step 5, repeating the previous four steps to obtain P time domain output samples each with a length of L<S,k>; and a frequency spectrum correction phase. The method provided by the invention is mainly applied to digital signal processing.

Description

technical field [0001] The invention belongs to the field of digital signal processing. It specifically involves digital filter design, signal sampling and filtering process, signal spectrum correction, and digital signal parameter recovery. Background technique [0002] At present, the problem of shortage of wireless channel spectrum resources is prominent. Multi-carrier transmission technology has become the mainstream modulation method because of its advantages of improving spectrum utilization [1], easily suppressing multipath effect and frequency selective fading [2]. Orthogonal Frequency Division Multiplexing (OFDM) has become an indispensable modulation technology in wireless communication since the fourth generation of mobile communication. In recent years, various implementation schemes of multi-carrier filter bank modulation technology have been proposed at home and abroad [3-5]. In order to meet the needs of flexible configuration of subband filter bandwidth, ce...

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Problems solved by technology

However, the literature [12] did not solve the problem of how to accurately estimate the frequency parameters of the high-rate input from the low-rate output of each subband filter in its fast convolution-based filter bank structure

In fact, in the adjustable filter bank, since the output sampling rate has changed compared with the input sampling rate, and there are differences in the width and center position of each sub-band, from the perspective of the low-speed output observation end, the frequency analysis The result will have a very large deviation from the ideal value at the source

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