Rohde & Schwarz FSWP Series - Receiving and Providing Trigger Signals

Basics on I/Q Data Acquisition and Processing
R&S
®
FSWP
26User Manual 1177.5856.02 ─ 07
Sample iq.tar files
If you have the optional R&S FSWP VSA application (R&S FSWP-K70), some sample
iq.tar files are provided in the C:/R_S/Instr/user/vsa/DemoSignals directory
on the R&S FSWP.
Furthermore, you can create your own iq.tar files in the I/Q Analyzer, see Chap-
ter 7.2, "How to Export and Import I/Q Data", on page 73.
Pre-trigger and post-trigger samples
In applications that use pre-triggers or post-triggers, if no pre-trigger or post-trigger
samples are specified in the I/Q data file, or too few trigger samples are provided to
satisfy the requirements of the application, the missing pre- or post-trigger values are
filled up with zeros. Superfluous samples in the file are dropped, if necessary. For pre-
trigger samples, values are filled up or omitted at the beginning of the capture buffer,
for post-trigger samples, values are filled up or omitted at the end of the capture buffer.
4.3 Receiving and Providing Trigger Signals
Using one of the "trigger" connectors of the R&S FSWP, the R&S FSWP can use a sig-
nal from an external device as a trigger to capture data. Alternatively, the internal trig-
ger signal used by the R&S FSWP can be output for use by other connected devices.
Using the same trigger on several devices is useful to synchronize the transmitted and
received signals within a measurement.
For details on the connectors see the R&S FSWP "Getting Started" manual.
External trigger as input
If the trigger signal for the R&S FSWP is provided by an external device, the trigger
signal source must be connected to the R&S FSWP and the trigger source must be
defined as "External" in the R&S FSWP.
Trigger output
The R&S FSWP can provide output to another device either to pass on the internal
trigger signal, or to indicate that the R&S FSWP itself is ready to trigger.
The trigger signal can be output by the R&S FSWP automatically, or manually by the
user. If it is provided automatically, a high signal is output when the R&S FSWP has
triggered due to a measurement start ( "Device Triggered" ), or when the R&S FSWP is
ready to receive a trigger signal after a measurement start ( "Trigger Armed" ).
Manual triggering
If the trigger output signal is initiated manually, the length and level (high/low) of the
trigger pulse is also user-definable. Note, however, that the trigger pulse level is always
opposite to the constant signal level defined by the output "Level" setting, e.g. for
"Level" = "High", a constant high signal is output to the connector until the "Send Trig-
ger" button is selected. Then, a low pulse is provided.
Receiving and Providing Trigger Signals