The use of Transform/X can be clarified by the following examples:

Example 1

N = 256 points
Fs = 1000 Hz  ......Sampling frequency
Delta_F = Fs ........Frequency resolution
               = Fs/N = 1000/256 = 3.9063 Hz/bin

A peak in the 45th bin corresponds to:
45 x 3.9063 = 175.78 Hz

Example 2

N = 512
Fs = 1000 Hz  ......Sampling frequency
Delta_F = Fs ........Frequency resolution
               = Fs/N = 1000/512 = 1.9531 Hz/bin

A peak in the 90th bin corresponds to:
90 x 1.9531 = 175.78 Hz

Note that in Transform/X, for an N point FFT, the output vectors are N/2 in size, the mirror image data is not returned from the method.

The Linear Prediction/X control can also be used for computing the frequency response using alternative algorithms and includes the "FreqResponse" method.