Stereo System User Manual

Triggering
CSA8000B & TDS8000B User Manual
3-43
Use a trigger source that is synchronized with the signal you are sampling and
displaying. Selection of your trigger source depends on your application, as
showninTable3--1.
Table 3- 1: Application-based triggering
Application Source to use
Communications (optical)
serial NRZ data si gnals
Set source t o Clock Recovery, set the clock-recovery type, and
use an optical sampling module equipped with a clock-recovery
option supporti ng t he speci fic data rate of the serial optical
signal.
A custom c lock recovery rate can be def ined by the user i f the
optical module s upports a conti nuous-rate clock recovery. Refer
to Sampling Modules Supported on page 1--4 to see those
modules that support continuous-rate clock recovery.
TDR measurement using an
electric al sampling modul e
equipped with TDR
Set source t o Internal Clock t o use the internal cl ock of the
instrument (TDR clock), and select the appropriate clock
frequency. Disconnect any signal connected to the External
10MHz Reference Input when usi ng the Internal cl ock.
Measurements on systems
with a synchronized pretrigger
signal
Set source t o External Direct or External Prescaler as
appropriate (see Trigger Source Connectors) and connect the
pretrigger si gnal.
Any applicati on requiring that
the input signal provide the
trigger
Set source t o External Direct or External Prescaler as
appropriate (see Trigger Source Connectors).Useasignal
splitter or power divi der to couple to both the Ext Direct or
Prescaler i nput and t he input channel, so that the sampled
signal is also the tri gger signal.
Any applicati on requiring that
you probe the trigger source
Set source t o External Direct, and use a Tektronix probe as
described in Probe-to-Trigger Source Connection on
page 3--44.
Any applicati on requiring that
you perform special measure-
ments usi ng gated t rigger.
Set source t o External Direct, and use a TTL connection to
trigger gate as described in To Use Gated Trigger on
page 3--50.
Trigger Source and ESD. Observe static precautions when coupling trigger
sources to this instrument.
CAUTION. Electrostatic-static damage can permanently degrade and damage the
inputs to this instrument, its sampling modules, and accessory probes. You must
take proper precautions; please read your sampling module user manual for
more information.