FIR filter generation
FIR filter coefficients for a filter with the given order and frequency cutoffs.
fir2(n, f, m, grid_n = 512, ramp_n = grid_n/20, window = hamming(n + 1))
n |
order of the filter (1 less than the length of the filter) |
f |
band edges, strictly increasing vector in the range [0, 1] where 1 is the Nyquist frequency. The first element must be 0 and the last element must be 1. If elements are identical, it indicates a jump in frequency response. |
m |
magnitude at band edges, a vector of |
grid_n |
length of ideal frequency response function
defaults to 512, should be a power of 2 bigger than |
ramp_n |
transition width for jumps in filter response
defaults to |
window |
smoothing window. The returned filter is the same shape as the smoothing window. |
The FIR filter coefficients, an array of length(n+1), of class Ma.
Original Octave version by Paul Kienzle, pkienzle@user.sf.net. Conversion to R by Tom Short.
Octave Forge http://octave.sf.net
f <- c(0, 0.3, 0.3, 0.6, 0.6, 1) m <- c(0, 0, 1, 1/2, 0, 0) fh <- freqz(fir2(100, f, m)) op <- par(mfrow = c(1, 2)) plot(f, m, type = "b", ylab = "magnitude", xlab = "Frequency") lines(fh$f / pi, abs(fh$h), col = "blue") # plot in dB: plot(f, 20*log10(m+1e-5), type = "b", ylab = "dB", xlab = "Frequency") lines(fh$f / pi, 20*log10(abs(fh$h)), col = "blue") par(op)
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