VTI Instruments EX1629 User Manual page 162

VTI Instruments Corp.
The groupDelay parameter is a measure of rate of change of the total phase shift with respect to angular frequency.
When IIR filters are enabled, this number is specific to the dc portion of the signal. When IIR filters are disabled,
this parameter reflects the group delay of the FIR filters only which are constant across all frequencies.
NOTE When setting channel filters on the EX1629, it is highly recommended that the same filter setting
be used for each group of sixteen channels (0 through 15, 16 through 31, and 32 through 47) as
this ensures the tightest relative timing between channels. For more information on IIR filtering
delays, please see the Group Delay discussion in Appendix B.
E
XAMPLE
ViSession instrumentHandle;
ViStatus status;
ViInt32 ftype, fxfrm, forder
ViReal64 ffreq, grpdly;
...
status = vtex1629_get_IIR_filter_configuration(instrumentHandle,
162
0,
&ftype,
&ffreq,
&fxfrm,
&forder,
&grpdly);
EX1629 Command Set