A half-band filter whose frequency response is weakly correlated with the number of digits of coefficient quantization

Abstract

The invention discloses a half-band filter structure with frequency response weakly correlated with coefficient quantization digit, comprising a pre-filtering module, a multi-channel selector module, an adder module, a multiplier module, and a delay function module. Under the condition of keeping a half-band filter transfer function unchanged, the dependence of the frequency response of the half-band filter on the coefficient quantization digit is reduced. The half-band filter is split into two cascaded sub filters, and the frequency response of one sub filter is independent of coefficient, so that the influence of the frequency response of the whole half-band filter on coefficient perturbation is reduced. Compared with the traditional implementation structure, the coefficient quantization digit required for achieving the same filter performance is smaller, and the operation burden in the process of filtering operation is reduced. Therefore, the power consumption is reduced, hardware resources are saved, and the cost is reduced.

Description

technical field [0001] The invention relates to the technical field of digital integrated circuits, in particular to a half-band filter whose frequency response is weakly correlated with the number of digits of coefficient quantization. Background technique [0002] In the communication system, interface circuit, software radio and other application fields, it is necessary to convert the sampling frequency of the digital signal, and the decimation filter completes the down-sampling of the signal. The decimation half-band filter is widely used in multi-rate signal processing systems because of its excellent passband ripple and stopband attenuation control capabilities. figure 1 It is a structural schematic diagram of a traditional decimation half-band filter, which consists of an anti-aliasing low-pass filter and a downsampling module. The down-sampling module performs down-sampling processing on the signal, that is, takes out one data every two clock cycles in the original ...

AI Technical Summary

Problems solved by technology

[0003] In the actual circuit implementation process, the frequency response of the half-band filter is greatly affected by the quantization of the filter coefficients, and the limited precision of the coefficient quantization will inevitably change the zero and pole points of the filter transfer function, thereby changing its frequency response; in order to reduce the coefficient The impact of quantization on the frequency characteristics of the filter, the number of quantized coefficients is generally larger, which will increase hardware overhead and area

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