Tektronix PSM3000 Series, User Manual

Page: 52 / 76

Pulse Pro fi ling Application
Response.
Use the Response function for correcting measurements through
devices like directional couplers. The Response function allows you to enter a set
of amplitude and frequency pairs. As you change the frequency of measurement,
the application automatically adjusts the offset based on the frequency you
selected.
The Response function must be enabled to affect measurements. The Response
annunciator is visible above and to the right of the measurement trace when the
Response function is enabled.
Minimize Undersampling.
For sweep times of 10 ms or less, equivalent-time
sampling (undersampling) is used to provide adequate time resolution and fi ll
the trace memory. The Minimize Undersampling function has no effect at these
sweep time settings.
For sweep times of 20 ms, 50 ms, and 100 ms, undersampling provides more
samples than are needed to
fi ll the trace memory. When Minimize Undersampling
is turned off, samples are averaged together to fi t into the 10,000 point trace. When
the Minimize Undersampling function is turned on, equivalent-time samples that
do not
fi t into the trace are not averaged, but are discarded. Activating this function
will tend to increase the noise on the trace, but it improves the ability to see peaks.
For sweep times of 200 ms or more, real-time sampling provides enough samples
to
fi ll the trace memory and to give adequate time resolution. Undersampling is
not used and the Minimize Undersampling function has no effect at these sweep
settings.
NOTE. You can read more about sweep time values. (See Table 3.)
Exit.
Select to exit the application.
Triggering & Delay
The Triggering and Delay toolbar allows you to set trigger and delay parameters.
Trigger Source. You have three options for trigger source settings. All of
these options allow you to use positive or negative Edge triggering, as well as
Continuous or Single Sweep.
Internal Auto Level : The trigger is based on the input signal. As the input varies,
the auto trigger level will be adjusted accordingly. This trigger mode always
returns a trace. A trigger pulse is sent out the TTL trigger output each time a
sweep starts. If a signal is not present, then it will return a noise trace. This trigger
source is not recommended when peak input levels fall below approximately
-50 dBm. In these cases, use Internal Manual Level.
38 RF and Microwave Power Sensors/Meters