Multiplies a series with a Kaiser window.
KAISER(series, ampflag, beta)
series |
- |
A series or array. | ||||||||||||
ampflag |
- |
Optional. An integer, the amplitude correction flag:
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beta |
- |
Optional. A real, the scaling factor. Defaults to 7.865. |
KAISER(N, ampflag, beta)
N |
- |
An integer, the window length. | ||||||||||||
ampflag |
- |
Optional. An integer, the amplitude correction flag:
| ||||||||||||
beta |
- |
Optional. A real, the scaling factor. Defaults to 7.865. |
A series or array.
W1: gsin(1000, .001, 45)
W2: spectrum(kaiser(W1))
W3: spectrum(kaiser(W1, 1))
The MAX of W2 == 0.4389 and the MAX of W3 == 1.0. The amplitude of the spectrum in W3 has been corrected to take into account amplitude effects of the Kaiser window.
If ampflag == 1, the correction factor is the mean of the spectral window. This assures that the spectrum of a sinusoid of amplitude A has a peak of A.
If ampflag == 2, the correction is applied as follows:
w = kaiser(s) * rms(s) / rms(kaiser(s))
This assures that:
sqrt(area(psd(w))) == rms(s) approximately
If ampflag == 3, the correction is applied as follows:
w = winfun(s) / sqrt(mean(win * win)
where win is the windowing function.
The Kaiser window is generated using the following formula:
where n is the n^{th} point (1 <= n <= N), I_{o} is the modified zeroth order Bessel function of the first kind. Default β is 7.865 and N is the number of points to generate.
See GKAISER to generate a Kaiser window.