sigwin.kaiser Class

Namespace: sigwin

Construct Kaiser window object

Description

Note

The use of sigwin.kaiser is not recommended. Use kaiser instead.

sigwin.kaiser creates a handle to a Kaiser 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 following equation defines the Kaiser window of length N:

$$w(x)=I_0\left(\beta \sqrt{1-\frac{4x^2}{{(N-1)}^2}}\right)/I_0(\beta ),-(N-1)/2\le x\le (N-1)/2$$

where x is linearly spaced N-point vector and $$I_0()$$ is the modified zeroth-order Bessel function of the first kind. $$\beta$$ is the attenuation parameter.

Construction

H = sigwin.kaiser returns a Kaiser window object H of length 64 and attenuation parameter beta of 0.5.

H = sigwin.kaiser(Length) returns a Kaiser window object H of length Length and attenuation parameter beta of 0.5. Length requires a positive integer. Entering a positive noninteger value for Length rounds the length to the nearest integer. Entering a 1 for Length results in a window with a single value of 1.

H = sigwin.kaiser(Length,Beta) returns a Kaiser window object with real-valued attenuation parameter beta.

Properties

Length	Kaiser window length. The window length requires a positive integer. Entering a positive noninteger value for Length rounds the length to the nearest integer. Entering a 1 for Length results in a window with a single value of 1.
Beta	Attenuation parameter. Beta requires a real number. Larger absolute values of Beta result in greater stopband attenuation, or equivalently greater attenuation between the main lobe and first side lobe.

Methods

generate	Generates Kaiser window
info	Display information about Kaiser window object
winwrite	Save Kaiser window 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

Kaiser Windows

Generate two Kaiser windows of length N = 64:

• The first window has an attenuation parameter β = 5.

• The second window has β = 15.

Display the two windows.

H05 = sigwin.kaiser(128,5);
H15 = sigwin.kaiser(128,15);

wvt = wvtool(H05,H15);
legend(wvt.CurrentAxes,'\beta = 5','\beta = 15')

Generate a Kaiser window with length N = 16 and the default β = 1/2. Return its values as a column vector. Show information about the window object. Display the window.

H = sigwin.kaiser(16);

win = generate(H)

win = 16×1

    0.9403
    0.9550
    0.9677
    0.9783
    0.9868
    0.9933
    0.9976
    0.9997
    0.9997
    0.9976
    0.9933
    0.9868
    0.9783
    0.9677
    0.9550
      ⋮

wininfo = info(H)

wininfo = 4×13 char array
    'Kaiser Window'
    '-------------'
    'Length  : 16 '
    'Beta    : 0.5'

wvtool(H)

References

Oppenheim, Alan V., and Ronald W. Schafer. Discrete-Time Signal Processing. Upper Saddle River, NJ: Prentice Hall, 1989.