Show Response

Once pole and/or  zero locations have been entered into  DST either from file (Choose from file option from the Poles/Zero menu or Open File with GSE Calibration from the File menu) or by entering them manually (Modify and Enter option from the Poles/Zeros menu), DST allows the evaluation and display of various properties of the frequency response function, the step response and the impulse response.

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.

>> Frequency Response

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 delay

For all quantities the axis type can be switched between various combinations of linear and logarithmic scale.

>> Impulse Response

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.

>> Step Response

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.