This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English verison of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.


Convert FIR Type I lowpass to FIR Type 1 lowpass with inverse bandwidth


g = firlp2lp(b)


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(π-w)].

When 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.


Overlay the original narrowband lowpass and the resulting wideband lowpass

b = firgr(36,[0 .2 .25 1],[1 1 0 0],[1 5]);
hold on
h = firlp2lp(b);


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.

See Also


Introduced in R2011a

Was this topic helpful?