Applying Phase correction to modify the duration of the signal.

Hello

I need to increase the duration of my signal by adding correction to Phase. I am using fft and I have estimated amplitude as well as phase of the signal. Now I am mofying (adding) the phase with increments, finally taking ifft to get the signal back, but I am not getting the desired results.

I can shift the signal in time using fft by fft(s)*exp(-iwto), however, I do not want to do that, I do not have the information about the delay time, I olny have the additional phase information which needs to be used to increase the duration of my signal.

CAN SOMEONE OFFER ME SOME HELP?

Thank You Jetson