Want to creat an inverse fft of a measured signal

I have a campbell-diagramm of a motor ramp. on the axes I have frequenz, time and the complexe value. Now I have to creat a real value over the time of this graph. For this I want to use the function ifft, but I neet the ifft with the parameter I used to creat the campbell-diagramm. And I don't now how to tell Matlab that I want too use the block size, the window that I want to use. The funcion of ifft(x,m,n) doesn't now which parameters it has to calculate with.. Thank you for your Help

[Salaheddin Hosseinzadeh]

What is this parameter you're talking about? Sampling frequency?! Is it something related to your literature?

[Simon Simon]

I am talking about sampling frequency, block size and the window (hanning, flattop). So I think, if matlab is using an other block size or doesn't now which window I used to creat the campbell-diagramm, it migth be a different result.