Agilent Technologies E1439, User Manual

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123
Agilent E1439 Programmer's Reference
Functions listed alphabetically
age1439_filter_sync
Synchronizes the decimation counter for multi-module systems.
VXI plug&play Syntax
#include "age1439".h
ViStatus age1439_filter_sync(ViSession id );
Description
This function causes the digital decimation counter to be reset by the next Sync line rising
transition. By calling
age1439_filter_sync for every Agilent E1439 module using a shared ADC
clock, and then calling age1439_meas_control to cause a sync transition, the decimation counters
are prepared to start at the same time. Once this is done the decimation counters stay synchronized
as long as the same ADC clock is used. You do not need to resynchronize the decimation counters
when the digital filter bandwidths are changed.
Note
Resetting the decimation counter causes a transient in the digital filters. The transient takes about
30 decimated output sample periods to decay 100 dB. See the step response graphs in the
Technical Specifications for more detail.
Parameters
id is the VXI instrument session pointer returned by the age1439_init function.
Comment
The correct procedure for using this command is:
1. Force all modules to idle using age1439_meas_control.
2. Call age1439_filter_sync for all modules.
3. Cause a sync transition with one module using age1439_meas_control without releasing
force to idle.
4. Release force to idle on all modules.
If you also want to synchronize frequency or phase see age1439_frequency_setup . This
procedure also applies to those commands for multi-module systems.
Example
The multichan.exe example program provides an example of how to correctly set up a multi-
module system with synchronous filters.
Return Value
AGE1439_SUCCESS indicates that a function was successful.
Values other than AGE1439_SUCCESS indicate an error condition or other important status
condition. To determine the error message, pass the return value to “age1439_error_message” on
page 102 .