% error: y = decimate(x, q [, n] [, ftype]) % % Downsample the signal x by a factor of q, using an order n filter % of ftype 'fir' or 'iir'. By default, an order 8 Chebyshev type I % filter is used or a 30 point FIR filter if ftype is 'fir'. Note % that q must be an integer for this rate change method. % % Example % %% Generate a signal that starts away from zero, is slowly varying % %% at the start and quickly varying at the end, decimate and plot. % %% Since it starts away from zero, you will see the boundary % %% effects of the antialiasing filter clearly. Next you will see % %% how it follows the curve nicely in the slowly varying early % %% part of the signal, but averages the curve in the quickly % %% varying late part of the signal. % t=0:0.01:2; x=chirp(t,2,.5,10,'quadratic')+sin(2*pi*t*0.4); % y = decimate(x,4); % factor of 4 decimation % stem(t(1:121)*1000,x(1:121),'-g;Original;'); hold on; % plot original % stem(t(1:4:121)*1000,y(1:31),'-r;Decimated;'); hold off; % decimated

- cheby1 % Generate an Chebyshev type I filter with Rp dB of pass band ripple.
- fftfilt %
- filtfilt % error: y = filtfilt(b, a, x)
- fir1 % error: b = fir1(n, w [, type] [, window] [, noscale])

Generated on Sat 16-May-2009 00:04:49 by