firpr2chfb

Two-channel FIR filter bank for perfect reconstruction

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Syntax

[h0,h1,g0,g1] = firpr2chfb(n,fp) [h0,h1,g0,g1] = firpr2chfb(n,dev,'dev') [h0,h1,g0,g1] = firpr2chfb('minorder',fp,dev)

Description

[h0,h1,g0,g1] = firpr2chfb(n,fp)designs four FIR filters for the analysis sections (h0andh1) and synthesis section is (g0andg1) of a two-channel perfect reconstruction filter bank. The design corresponds to the orthogonal filter banks also known as power-symmetric filter banks.

nis the order of all four filters. It must be an odd integer.fpis the passband-edge for the lowpass filtersh0andg0. The passband-edge argumentfpmust be less than 0.5.h1andg1are highpass filters with the passband-edge given by (1-fp).

[h0,h1,g0,g1] = firpr2chfb(n,dev,'dev')designs the four filters such that the maximum stopband ripple ofh0is given by the scalardev. Specifydev在线性单元,而不是分贝。The stopband-ripple ofh1is also be given bydev, while the maximum stopband-ripple for bothg0andg1is (2*dev).

[h0,h1,g0,g1] = firpr2chfb('minorder',fp,dev)designs the four filters such thath0meets the passband-edge specificationfpand the stopband-rippledevusing minimum order filters to meet the specification.

Examples

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Design a Filter Bank Using firpr2chfb

Open Script

Design a filter bank with filters of order n equal to 99 and passband edges of 0.45 and 0.55.

n = 99; [h0,h1,g0,g1] = firpr2chfb(n,.45); fvtool(h0,1,h1,1,g0,1,g1,1);

Here are the filters, showing clearly the passband edges.

Use the following stem plots to verify perfect reconstruction using the filter bank created by firpr2chfb.

stem(1/2*conv(g0,h0)+1/2*conv(g1,h1)) n=0:n; stem(1/2*conv((-1).^n.*h0,g0)+1/2*conv((-1).^n.*h1,g1)) stem(1/2*conv((-1).^n.*g0,h0)+1/2*conv((-1).^n.*g1,h1)) stem(1/2*conv((-1).^n.*g0,(-1).^n.*h0)+...1/2*conv((-1).^n.*g1,(-1).^n.*h1)) stem(conv((-1).^n.*h1,h0)-conv((-1).^n.*h0,h1))