HP 8920A - Page 480

480
S:\HP892XX\USRGUIDE\manual\rfanscrn.fb
Chapter 17, RF Analyzer Screen
Field Descriptions
TX Power
Transmitter power measures RF power at the RF IN/OUT port.
Operating Considerations
Maximum signal levels at each port are printed on the front panel.
Only the RF IN/OUT port can be used for measuring TX power on this screen.
When the
Input Port is set to Ant, four dashes (- - - -) appear in place of digits
for this measurement.
Use the Spectrum Analyzer
1
to measure low-level RF power (≤200 mW) at the
ANT IN port.
1. Spectrum Analyzer is optional on some Test Set models.
CAUTION: Connecting a signal of >200 mW to the ANT IN port can cause instrument damage (although
internal protection circuits can typically withstand a short-duration signal of 1 or 2 Watts).
If the overpower circuit is triggered (signified by a warning message at the top of
the screen), remove the signal from the ANT IN port, and press
[MEAS RESET] or turn the Test Set off and on to reset it.
See Also
Input Port
field description, on page 476 (Operating Considerations)
TX Power field description (this page)
TX Pwr Zero
field description, on page 480.
TX Pwr Zero
The transmitter power zero function establishes a 0.0000 W reference for
measuring RF power at the RF IN/OUT port.
RF power must not be applied while zeroing. Set the RF GENERATOR screen Ampli-
tude field to off to prevent internal cross-coupling into the power detector while zeroing.
Operating Considerations
When power is applied to the RF IN/OUT connector, the temperature of the
internal circuitry increases. This can cause changes in the
TX Power
measurement when low power levels are measured immediately following high
power measurements.