Measuring Tdma Signals; Power Meter And Sensor Operation; Achieving Stable Results With Tdma Signals - Keysight Technologies E Series Operating And Service Manual

2 Making Measurements

Measuring TDMA Signals

Power meter and sensor operation

The voltages generated by the diode detectors in the power sensor can be very
small. Gain and signal conditioning are required to allow accurate measurement.
This is achieved using a 220 Hz (440 Hz in fast mode) square wave output from
the power meter to drive a chopper-amplifier in the power sensor. Digital Signal
Processing (DSP) of the generated square wave is used by the power meter to
recover the power sensor output and accurately calculate the power level.
The chopper-amplifier technique provides noise immunity and allows large
physical distances between power sensor and power meter (Keysight 11730
series cables available up to 61 metres). Additional averaging helps reduce noise
susceptibility.

Achieving stable results with TDMA signals

The averaging settings in the power meter are designed to reduce noise when
measuring continuous wave (CW) signals. Initial measurement of a pulsed signal
may appear unstable with jitter on the less significant displayed digits. With
pulsed signals the averaging period must be increased to allow measurement over
many cycles of the pulsed signal.
To set the averaging proceed as follows:
The example shows the key labels for a single channel power meter. Dual
NOTE
channel meter are similar, adding only channel identification to the softkey
labels.
1 Press
2 The filter setting is displayed under the
36
Input Settings
,
the filter menu.
setting first set manual mode by pressing the
highlight Man .
, . Press the
Length
Keysight E-Series E9300 Operating and Service Guide
Filter
softkey to access
softkey label. To change this
softkey to
Mode Man Auto