sigwin.chebwin class

Package: sigwin

Construct Dolph-Chebyshev window object

Description

sigwin.chebwin creates a handle to a Dolph–Chebyshev window object for use in spectral analysis and FIR filtering by the window method. Object methods enable workspace import and ASCII file export of the window values.

The Dolph-Chebyshev window is constructed in the frequency domain by taking samples of the window's Fourier transform:

W^(k)=(1)kcos[Ncos1[βcos(πk/N)]]cosh[Ncosh1(β)]0kN1

where

β=cos[1/Ncosh1(10α)]

α determines the level of the sidelobe attenuation. The level of the sidelobe attenuation is equal to 20α. For example, 100 dB of attenuation results from setting α=5

The discrete-time Dolph-Chebyshev window is obtained by taking the inverse DFT of W^(k) and scaling the result to have a peak value of 1.

Construction

H = sigwin.chebwin returns a Dolph-Chebyshev window object H of length 64 with relative sidelobe attenuation of 100 dB.

H = sigwin.chebwin(Length) returns a Dolph–Chebyshev window object H of length Length with relative sidelobe attenuation of 100 dB. Length requires a positive integer. Entering a positive noninteger value for Length rounds the length to the nearest integer. A window length of 1 results in a window with a single value equal to 1.

H = sigwin.chebwin(Length,SidelobeAtten) returns a Dolph-Chebyshev window object with relative sidelobe attenuation of atten_param dB.

Properties

Length

Dolph-Chebyshev window length.

SidelobeAtten

The attenuation parameter in dB. The attenuation parameter is a positive real number that determines the relative sidelobe attenuation of the window.

Methods

generateGenerates Dolph-Chebyshev window
infoDisplay information about Dolph–Chebyshev window object
winwriteSave Dolph-Chebyshev window object values in ASCII file

Copy Semantics

Handle. To learn how copy semantics affect your use of the class, see Copying Objects in the MATLAB® Programming Fundamentals documentation.

Examples

Default length N=64 Dolph–Chebyshev window with 100 dB relative sidelobe attenuation:

H=sigwin.chebwin;
wvtool(H); 

Generate length N=128 Chebyshev window with 120 dB attenuation, return values, and write ASCII file:

H=sigwin.chebwin(128,120);
% Return window with generate
win=generate(H);
% Write ASCII file in current directory
% with window values
winwrite(H,'chebwin_128_100')

References

Harris.F.J. "On the Use of Windows for Harmonic Analysis with the Discrete Fourier Transform." Proceedings of the IEEE®. Vol. 66, 1978, pp. 51–83.

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