# kaiserAtten function Null safety

double kaiserAtten(
1. int numtaps,
2. double width
)

Compute the attenuation of a Kaiser FIR filter. Given the number of taps `N` and the transition width `width`, compute the attenuation `a` in dB, given by Kaiser's formula: a = 2.285 * (N - 1) * pi * width + 7.95

# Parameters

• `numtaps` : The number of taps in the FIR filter.
• `width` : The desired width of the transition region between passband and stopband (or, in general, at any discontinuity) for the filter, expressed as a fraction of the Nyquist frequency.

# Returns

• a : The attenuation of the ripple, in dB.

• kaiserord, kaiser_beta

# Examples

``````// Suppose we want to design a FIR filter using the Kaiser window method
// that will have 211 taps and a transition width of 9 Hz for a signal that
// is sampled at 480 Hz.  Expressed as a fraction of the Nyquist frequency,
// the width is 9/(0.5*480) = 0.0375.  The approximate attenuation (in dB)
// is computed as follows:
print(kaiser_atten(211, 0.0375));

/* output:
64.48099630593983
*/
``````

## Implementation

``````double kaiserAtten(int numtaps, double width) {
var a = 2.285 * (numtaps - 1) * pi * width + 7.95;
return a;
}``````