Technical data

266 Chapter 9
Channel Scanner
Using the Channel Scanner
Channel Scanner
NOTE The autoranging feature under [Setup], [Range Control] that is built into the test set
helps ensure accurate measurements by changing front-end amplifier gain as
needed. This might be, for example, when a strong signal threatens to overload the
test set. When this occurs, the noise floor rises (as gain is decreased), then falls again
when the strong signal stops.
If you prefer a fixed noise floor, you can disable autoranging in two ways using the
Setup function within Channel Scanner:
• On [Range Ctrl] select
Hold to fix the noise floor at the current level. A
subsequent strong signal—even outside the measurement range—may cause an
inaccurate reading due to overloading the front-end of the test set.
• On [Range Ctrl] select
Max to fix the noise floor at the current level until a
strong signal comes in. In that case, the floor will rise to maintain accuracy, but
will not return to its lower level after the strong signal stops.
Displaying Accurate Peak Power (Recommended for Pulsed
Signals)
For pulsed signals, you can get a more accurate measurement of the signal’s peak or
average power by using the Peak Power Detector setting.
The test set measures average power of signals by default. But for
non-constant-duty-cycle signals such as GSM, an average power reading fails to
accurately show amplitude when the signal is on if other timeslots in the frame are
powered off.
If the [Power Detector] menu key is grayed out, the test set needs to be upgraded in
order to measure pulsed signals. Contact the Agilent Service Center for upgrade
information.
Step Notes
1[Setup]
2 On [Power Detector] select
Pk. Each time you press this softkey, the
selected option changes.