The amplitude spectrum is placed starting at the output time of 300 ms, which corresponds to the start of the dataset. My first sample point will correspond to 0 Hz and my 16th data point will correspond to 250 Hz. For a 63 ms window, this corresponds to a frequency resolution of ( 1/0.063 = ) 16 Hz. In my case, my dataset has a 2 ms sampling rate which corresponds to a Nyquist of 250 Hz (= 1/(2*0.002) ). The frequency resolution is given by the inverse of the time window. Dft_hamp.prsĩ You ll also need to know something about the DFT and the script The Trace Maths script will plot the amplitude spectrum starting from 0 Hz up to the positive Nyquist frequency. Click on the icon below to copy and paste the DFT Trace Maths script to your system. The spectrum will be output starting from 300 ms. In this case, I m starting at the Lower_Mannville horizon and using a 63 ms window. You will have to edit the start time (t1 = ), the window length (wlen = ) and the output time. I am going to calculate the spectra over a 63 ms window in this example.Ĩ Copy and paste the DFT_Hamp.prs Trace Maths script into the Trace Maths window. 7 Call the output volume something meaningful.