how to express sinc * exp?

[eric]

Dear octave expert:

  In matlab toolbox siganl processing:
b=0.4*sinc(0.4*(-25:25));
[H,w]=freqz(b,1,512,2);
plot(w,abs(H));

work
 
but if I want to let b be the product of sinc and
2*exp(-i*pi)+exp(-i*3*pi)
b=0.4*sinc*(2*exp(-i*pi)+exp(-i*3*pi))(0.4*(-25:25));

is not work,
I got
x undefined near line 24 column 37
..................
etc.

how to modify it to work?

need and thanks your help
Eric(address@hidden)



-----------------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.che.wisc.edu/octave/octave.html
How to fund new projects:  http://www.che.wisc.edu/octave/funding.html
Subscription information:  http://www.che.wisc.edu/octave/archive.html
-----------------------------------------------------------------------