Fractional Delay Optimization Applicable to Multiple Nyquist Zones and Its Realization Structure

Abstract

A fractional delay optimization method suitable for multiple Nyquist zones and its realization structure belong to the field of digital signal processing. Perform fractional delay processing on the input data sequence to obtain the first output data sequence and do multiplication, then perform Hilbert transform to obtain the second output data sequence, and then subtract the first output data sequence from the second output data sequence to obtain the applicable The output data sequence after a fractional delay in the Donor Nyquist zone, where the multiplication operation multiplies the input data sequence by a scaling factor A = (‑1) NZ ceil[(NZ‑1) / 2] 2πD, where NZ represents the Nyquist zone where the frequency fin of the input data sequence is located relative to the sampling frequency fs, and ceil represents the upward fetching of the data (NZ‑1) / 2 Integer operation, D represents the delay amount of the fractional delay filter. The invention can extend the application frequency range of the traditional fractional delay filter to the high Nyquist zone, realize the fractional delay in the multi-Nyquist zone, and has a simple structure and is easy to realize.

Description

technical field [0001] The invention relates to the field of digital signal processing, in particular to a fractional delay optimization method suitable for multiple Nyquist zones and the design of a fractional delay filter suitable for multiple Nyquist zones. Background technique [0002] Fractional delay filter, also known as continuously variable digital delay unit, is a digital filter with a delay of non-integer samples, widely used in speech coding and synthesis, digital communication, delay estimation, and sampling rate conversion and other fields. [0003] There are relatively mature design methods for fractional delay filters, such as the design method based on polynomials (Farrow structure), the design method based on Lagrangian interpolation method, and the design method based on least squares method. However, the disadvantage of the fractional delay filter designed by the traditional method is that its application frequency band is in the first Nyquist zone (0 ~ ...

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Problems solved by technology

However, the disadvantage of the fractional delay filter designed by the traditional method is that its application frequency band is in the first Nyquist zone (0 ~ fs / 2, fs represents the sampling rate of the digital signal), and the application frequency band refers to the filter The input signal frequency (fin) range that the filter can handle, so when fin exceeds fs / 2, the fractional delay filter cannot work normally, which greatly limits the application range of the fractional delay filter

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