Digital decimation filter

Abstract

The invention provides a digital decimation filter. The digital decimation filter comprises a cascade integral comb filter, a cascaded Lagrange half-band filter and an FIR filter, which are orderly connected. The digital decimation filter has the advantages of less pass band dropping, small quantized noise power after filtering, and less power consumption.

Description

technical field [0001] The present invention relates to filters, in particular to a digital decimation filter. Background technique [0002] A digital decimation filter (Digital Decimation Filter) is applied in an analog-to-digital converter (ADC) based on Σ-Δ modulation. Analog-to-digital converters based on sigma-delta modulation use oversampling, noise shaping, and digital decimation filters to achieve higher signal-to-noise ratios. Oversampling is used because: As the multiple R increases, the quantization noise spectrum overlaps with the signal spectrum less and less. Noise shaping concentrates the noise energy to high frequencies. The digital decimation filter eliminates quantization noise within the frequency band π / R<|ω|≤π without changing the signal components, thus improving the signal-to-noise ratio. Digital decimation filters can be used not only in ADCs based on Σ-Δ modulation, but also in digital down converters (DDC) and digital up converters (DUC). [...

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to provide a digital decimation filter, which aims to solve the problem that the attenuation of the half-band filter of the existing digital decimation filter is not large enough in the aliasing band, the tap coefficients are complex, and the existing digital decimation filter The problem of large passband drop caused by

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