function KaiserBetaFir(Ripple: Double): Double;
Kaiser beta for a FIR filter with a given ripple.
| # | Name | Type | Description |
|---|---|---|---|
| 1 | Ripple | Double | scalar |
Returns: Double
Remarks:
Returns the Kaiser-window shape parameter beta that yields the requested passband/stopband Ripple in a windowed FIR design. With A = -20log_(10)(Ripple) the attenuation in dB, the standard empirical formula is
beta = { 0.1102 (A-8.7), if A > 50
{ 0.5842 (A-21)^(0.4) + 0.07886 (A-21), if 21 <= A <= 50
{ 0, if A < 21
Domain: 0 < Ripple < 1. The result feeds the Beta argument of Kaiser / KaiserImpulse. A larger ripple (less attenuation) gives a smaller beta; below 21 dB no windowing is needed and beta = 0.
References:
[1] Discrete-time signal processing, Oppenheim and Schafer, Prentice-Hall, 1989.
See Also: SignalUtils.Kaiser, SignalUtils.KaiserBetaWindow