I need to convert 150 Frequency domain samples to the time domain. The problem is, I have been provided with 250 time domain samples for comparing my results.  How am I supposed to relate the 150 samples to 250 samples? I can't find any relationship like interpolation/decimation between the two.

Does this have anything to do with windowing (hamming,hanning,etc), sampling frequency, min and max frequency in the original signal?

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@Jim: I have 150 frequency domain samples and i need to get 250 time domain samples using them. If I do a normal iFFT, I would get only 150 TD samples. So I tried to append 100 zeros to the FD samples and then did the iFFT. But then, my samples are different from the original answers.

The input set I have is : 150 TD samples, sampling frequency=10GHZ, Min and Max frequency of the original signal = 500MHZ and 3050 MHZ, Window= Kaiser (beta=6)

I believe that I have been provided with either insufficient or incorrect data.
Am i right?