Anritsu 0701012 - Manual (Page 34)

Measurement Considerations Using the Power Sensor
3-16 MA24106A UG
For example, a CW tone at –30 dBm is to be measured to 0.01 dB resolution. Using the table in the sensor
manual, the required number of averages is 38 averages using High Aperture Time mode (the same
measurement would require more than 256 averages in Low Aperture Time mode).
Settling Time
The MA24106A samples power continuously every 70 ms in the Low Aperture Time (LAT) mode and 700 ms in
the High Aperture Time (HAT) mode. The sensor’s front end and digitizer settles completely to a step change in
power in this amount of time. However, there is no way to synchronize the sensor’s sampling to any other
event, such as a power step or bus request for a measurement. Therefore, the first measurement requested
from the sensor after a power step may not be fully settled. To ensure a fully settled measurement when
operating the sensor over the bus, wait 70 ms (700 ms if in HAT) after a power step before requesting the
measurement from the sensor. Alternatively, request two measurements from the sensor and discard the first.
If averaging is required as described above, settling time increases by N × sample period, where N is the
number of averages and the sample period is the time is milliseconds. The measurement sample period is
70 ms for LAT and 700 ms for HAT. When operating the sensor over the bus, request N+1 measurements from
the sensor, discard the first, and then average the subsequent readings. The settling time is approximately
(N+1) × sample period.