iirpeak (Digital Filter Design Toolkit, MathScript Function)

LabVIEW 8.6 Digital Filter Design Toolkit Help
June 2008

NI Part Number:
371988B-01

»View Product Info

Owning Class: singlerate

Syntax

[b, a] = iirpeak(w, bw)

[b, a] = iirpeak(w, bw, ab)

Name	Description
w	Specifies the center frequency of the filter peak. w is a double-precision, floating-point number that must fall in the range (0, 1).
bw	Specifies the bandwidth of the filter peak at -ab dB. bw is a double-precision, floating-point number that must fall in the range (0, 1).
ab	Specifies the attenuation, in decibels, that corresponds to the bandwidth bw. ab is a double-precision, floating-point number greater than zero. The default is 3.0103, which corresponds to a 3 dB bandwidth, a commonly used bandwidth for a filter.

Name	Description
b	Returns the numerator of the designed IIR filter. b is a three-element real vector.
a	Returns the denominator of the designed IIR filter. a is a three-element real vector.

[b, a] = iirpeak(0.1, 0.001);
fft_mag = abs(fft(b, 16384)./fft(a, 16384));
figure;
plot(0:1/8192:1, fft_mag(1:8193));