I want to shift the phase of a Ricker wavelet by a constant value (i.e. 45 degree) in MATLAB.
Can anyone help me please?
Hello,
I imagine you are using the following equation to compute the Ricker Wavelet:
Equation 1: s=(((1-2*pi^2*f^2*(t).^2).*exp(-pi^2*f^2*(t).^2)));
If you want to perform a Phase Shift in time domain you need only to multiply your wavelet by exp(i*ang) where ang is the degree of the phase shift in radians.
Equation 2: (Ricker wavelet shifted by 45º) s.*exp(i*pi/4)
Noticed the usage of the dot product, because this is a pointwised multiplication.
Best,
Wanderson
Thanks Mr. Ferrira but I think your answer isn't correct because by this equation the shape of wavelet doesn't change
Oh, I see what you mean now. I was talking about a shift in time domain, for example delaying the wavelet two or three samples. My mistake.
I wrote the following code in MATLAB to answer your question. There is a plot attached too.
Best,
Wanderson
%Ricker wavelet analysis
t = (-(0.1):0.001:0.1)'; %time series
Fc = 30; %central frequency
p = Fc.*Fc.*t.*t;
amplitude = (1-2*pi*pi.*p).*exp(-pi*pi.*p);
plot(t,amplitude)
ylabel('Amplitude')
xlabel('Timeseries (s)')
grid on
%wavelet phase rotated
phase = 90; %degrees
phase = phase*pi/180; %radians
x = hilbert(amplitude); %hilbert transform
x2 = cos(phase)*real(x) - sin(phase)*imag(x);
hold on
plot(t,x2,'-r')
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