I am using fdesign.decimator to design an equiripple filter with given specifications. I have recently upgraded from R2007b to R2010a. In R2007b, this code output a filter with 89 coefficients, but the same code in R2010a results in a filter with 127 taps. This is breaking compatibility for my downstream code as I am using the filter and the signal output from the filter as a reference to compare with my filter code written in assembly. Compare the output generated by the following code in R2007a and R2010a:
Fpass = 3400; % Passband Frequency
Fstop = 4000; % Stopband Frequency Apass = 0.01; % Passband Ripple (dB) Astop = 80; % Stopband Attenuation (dB) Fs = 16000; % Sampling Frequency h = fdesign.decimator(2, 'Lowpass', 'fp,fst,ap,ast', Fpass, Fstop, … Apass, Astop, Fs); Hd = design(h, 'equiripple', … 'FilterStructure', 'firdecim', … 'MinPhase', true, … 'MinOrder', 'any', … 'StopbandShape', 'flat');
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