iircomb (Digital Filter Design Toolkit, MathScript Function)
Owning Class: singlerate
Syntax
[b, a] = iircomb(n, bw)
[b, a] = iircomb(n, bw, ab)
[b, a] = iircomb(n, bw, t)
[b, a] = iircomb(n, bw, ab, t)
Description
Designs an infinite impulse response (IIR) comb filter.
Inputs
| Name | Description | ||||
| n | Specifies the order of the filter. n is a positive integer. | ||||
| bw | Specifies the bandwidth of the filter notch or peak at -ab dB. bw is a double-precision, floating-point number that must fall in the range (0, 2/n). | ||||
| 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. | ||||
| t | Specifies the type of IIR comb filter you want to design. t is a string that accepts the following values:
|
Outputs
| Name | Description |
| b | Returns the numerator of the designed IIR filter. b is a real vector with a length of n+1. |
| a | Returns the denominator of the designed IIR filter. a is a real vector with a length of n+1. |
Examples
[b, a] = iircomb(10, 0.001, 3.0103);
fft_mag = abs(fft(b, 16384)./fft(a, 16384));
figure;
plot(0:1/8192:1, fft_mag(1:8193));
[b, a] = iircomb(10, 0.001, 3.0103, 'peak');
fft_mag = abs(fft(b, 16384)./fft(a, 16384));
figure;
plot(0:1/8192:1, fft_mag(1:8193));