

Newbie level 5
Equation for band stop filter
show that below equivalent introduce a band stop filter:
y=[e^x'(t)]cos(wt+x(t))
x'(t) is the hilbert transformation of x(t).

27th May 2007, 20:10

Advanced Member level 2
Re: band stop filter
Hi,
as an example case, i took x(t) to be sin(t) and x'(t) would then be cos(t). and then i implemented the formula u have given in matlab as,
y = exp(cos(2 * pi * 10 * t)) .* cos( 2 * pi * f1 * t + sin(2* pi * 10 * t));
here, i dint know what to assume for f1... i took the value as the 10 Hz input sine wave itself. i took the transform of y and divided by transform of sin(t) which is x(t) to get the frequency response H(w) and took the ifft to get impulse response h(t). and i used freqz(h) to get the mag and phase response.
And, It dint look like a band stop filter... What did I do wrong here? If this question is right to be proved...
regards,
cedance.