Filter Design Toolbox

firlp2lp

Convert FIR Type I lowpass to FIR Type 1 lowpass with inverse band width.

Syntax

• g = firlp2lp(b)
  

Description

g = firlp2lp(b) transforms the Type I lowpass FIR filter b with zero-phase response Hr(w) to a Type I lowpass FIR filter g with zero-phase response [1 - Hr(-w)].

If b is a narrowband filter, g will be a wideband filter and vice versa. The passband and stopband ripples of g will be equal to the stopband and passband ripples of b.

Examples

Overlay the original narrowband lowpass and the resulting wideband lowpass

• b = gremez(36,[0 .2 .25 1],[1 1 0 0],[1 5]);
  zerophase(b);
  hold on
  h = firlp2lp(b); 
  zerophase(h); hold off
  

See Also

firlp2hp

zerophase in your Signal Processing Toolbox documentation

References

[1]  Saramaki, T, Finite Impulse Response Filter Design, Handbook for Digital Signal Processing. S.K. Mitra and J.F. Kaiser Eds. Wiley-Interscience, N.Y., 1993, Chapter 4.

firhalfband

firlp2hp