# firhalfband (Digital Filter Design Toolkit, MathScript Function)

Owning Class: multirate

## Syntax

b = firhalfband(n, f)

b = firhalfband(n, f, 'high')

b = firhalfband('minorder', f, ripple)

b = firhalfband('minorder', f, ripple, 'kaiser')

b = firhalfband('minorder', f, ripple, 'kaiser', 'high')

Examples

## Inputs

 Name Description n Specifies the order of the filter. n is an even, positive number. If you do not specify n, you must specify a valid value for 'minorder'. f Specifies the passband edge frequency. f is a double-precision, floating-point number that must fall in the range (0, 0.5). 'high' Specifies that b returns a highpass, halfband FIR filter. If you do not specify 'high', b returns a lowpass, halfband FIR filter. 'minorder' Specifies that b returns a filter with the minimum order that meets the design requirements. If you do not specify 'minorder', you must specify a valid value for n. ripple Specifies the maximum ripple in the passband and stopband. ripple is a double-precision, floating-point number that must fall in the range (0, 1). 'kaiser' Specifies whether to use the Kaiser Window method to design the filter. If you do not specify 'kaiser', this function uses the Remez method to design the filter.

## Outputs

 Name Description b Returns the coefficients of the designed FIR filter. b is a real vector with a length of n+1 or 'minorder'+1.

## Examples

b = firhalfband(20, 0.4);figure;
freqz(b);

b = firhalfband('minorder', 0.4, 0.001);
figure;
freqz(b);