freqs

(/tools/hpmatlab/toolbox/signal/freqs.m)

Function Synopsis

[h,ww] = freqs(b,a,w)

Help text

FREQS	Laplace-transform (s-domain) frequency response.  
	H = FREQS(B,A,W) returns the complex frequency response vector H 
	of the filter B/A:
	                     nb-1      nb-2
		 B(s)   b(1)s  +  b(2)s   + ... +  b(nb)
	  H(s) = ---- = --------------------------------
	                     na-1      na-2
		 A(s)   a(1)s  +  a(2)s   + ... +  a(na)

	given the numerator and denominator coefficients in vectors B and A. 
	The frequency response is evaluated at the points specified in 
	vector W.  The magnitude and phase can be graphed by calling
	FREQS(B,A,W) with no output arguments.

	[H,W] = FREQS(B,A) automatically picks a set of 200 frequencies W on 
	which the frequency response is computed.  FREQS(B,A,N) picks N 
	frequencies. 

	See also LOGSPACE, POLYVAL, INVFREQS, and FREQZ.

Cross-Reference Information

abs            /tools/hpmatlab/toolbox/matlab/elfun/abs.m
angle          /tools/hpmatlab/toolbox/matlab/elfun/angle.m
axes           /tools/hpmatlab/toolbox/matlab/graphics/axes.m
elseif         /tools/hpmatlab/toolbox/matlab/lang/elseif.m
end            /tools/hpmatlab/toolbox/matlab/lang/end.m
freqint        /tools/hpmatlab/toolbox/signal/freqint.m
gca            /tools/hpmatlab/toolbox/matlab/graphics/gca.m
if             /tools/hpmatlab/toolbox/matlab/lang/if.m
length         /tools/hpmatlab/toolbox/matlab/general/length.m
linspace       /tools/hpmatlab/toolbox/matlab/elmat/linspace.m
log10          /tools/hpmatlab/toolbox/matlab/elfun/log10.m
loglog         /tools/hpmatlab/toolbox/matlab/plotxy/loglog.m
nargin         /tools/hpmatlab/toolbox/matlab/elmat/nargin.m
nargout        /tools/hpmatlab/toolbox/matlab/elmat/nargout.m
newplot        /tools/hpmatlab/toolbox/matlab/graphics/newplot.m
pi             /tools/hpmatlab/toolbox/matlab/elmat/pi.m
semilogx       /tools/hpmatlab/toolbox/matlab/plotxy/semilogx.m
set            /tools/hpmatlab/toolbox/matlab/graphics/set.m
sqrt           /tools/hpmatlab/toolbox/matlab/elfun/sqrt.m
subplot        /tools/hpmatlab/toolbox/matlab/graphics/subplot.m
xlabel         /tools/hpmatlab/toolbox/matlab/plotxy/xlabel.m
ylabel         /tools/hpmatlab/toolbox/matlab/plotxy/ylabel.m

filtdemo       /tools/hpmatlab/toolbox/signal/filtdemo.m