The frequency response function is calculated using a Fast Fourier Transform (FFT) algorithm. The frequency range for which the frequency response is evaluated ranges from DELTAF = FDIG/NFFT to FDIG/2. Here FDIG is the internal sampling frequency and NFFT is the number of points used for calculating the FFT. Both values can be entered or modified in the Setup menu to obtain a particular frequency range. In the context of using the FFT algorithm the window length has to be a power of 2. If this is not the case the user will be prompted for a proper value.
The user has to select the quantity of the frequency response to display. The possible options are:
->Phase shift
->Real part
->Imaginary part
->Group delay
->Phase delayFor all quantities the axis type can be switched between various combinations of linear and logarithmic scale.
Using the Impulse Response option, the time domain response to a discrete impulse (spike) at a selectable position defined in the Setup menu is calculated and played.
Using the Step Response option, the time domain response to a discrete step function (integrated spike) at a selectable position defined in the Setup menu is calculated and displayed.