Consider voltage vector x
Let the frequency shift be delta_f and phase shift be delta_p
N = 10000 % number of samples
To change the frequency of the data set, multiply complex exponential with x
y = exp(i*2*pi*[1:N]*delta_f*1/N).*x
Observe the fft plot with new frequency
plot(abs(fft(y)))
New frequency f_new = 450 + delta_f;
To add phase use circshift function on abs(y) shifted with delta_p
