Signal Processing Toolbox

freqspace

Frequency spacing for frequency response.

Syntax

f = freqspace(n)
f = freqspace(n,'whole')
[f1,f2] = freqspace(n)
[f1,f2] = freqspace([m n])
[x1,y1] = freqspace(n,'meshgrid')
[x1,y1] = freqspace([m n],'meshgrid')

Description

freqspace returns the implied frequency range for equally spaced frequency responses. This is useful when creating frequency vectors for use with freqz.

f = freqspace(n) returns the frequency vector f assuming n evenly spaced points around the unit circle. For n even or odd, f is (0:2/n:1). For n even, freqspace returns (n + 2)/2 points. For N odd, it returns (n + 1)/2 points.

f = freqspace(n,'whole') returns n evenly spaced points around the whole unit circle. In this case, f is 0:2/n:2*(n-1)/n.

[f1,f2] = freqspace(n) returns the two-dimensional frequency vectors f1 and f2 for an n-by-n matrix. For n odd, both f1 and f2 are [-1 + 1/n:2/n:1-1/n]. For n even, both f1 and f2 are [-1:2/n:1-2/n].

[f1,f2] = freqspace([m n]) returns the two-dimensional frequency vectors f1 and f2 for an m-by-n matrix.

[x1,y1] = freqspace(n,'meshgrid') and

[x1,y1] = freqspace([m n],'meshgrid') are equivalent to

[f1,f2] = freqspace(...);
[x1,y1] = meshgrid(f1,f2);

See the MATLAB documentation for details on the meshgrid function.

See Also

freqz	Compute the frequency response of digital filters.
invfreqz	Discrete-time filter identification from frequency data.

freqs

freqz