How To Set The Averaging Time - Agilent Technologies 8163A User Manual

Power Measurement
−50 dBm
−60 dBm
−70 dBm
94
Table 7 Upper Power Limits and Resolution for Various Power Ranges
[R ] Upper Power Limit
ANGE
19.999 nW
1.9999 nW
199.99 pW

How to Set the Averaging Time

N O TE
For a Dual Power Sensor, you cannot set the averaging time of the
slave channel, channel 2, directly. By default, the averaging time of the
slave channel, channel 2, is the same value as that for the master
channel, channel 1. See Table 8 on page 101 for more details.
This is the length of time over which a signal is averaged. Longer
averaging times increase the accuracy and improve the noise rejection.
Longer averaging times also decrease sensitivity.
For averaging times of 1 second or less, a new measurement is shown
at the end of each averaging time. This is drawn in Figure 52. A new
measurement is shown on the display at each x.
T
avg
x x x
Measurements with Tavg ≤ 1 second
Figure 52
With modules designed for the HP 8153A Lightwave Multimeter, for
averaging times of more than 1 second, the displayed power is given by
the formula:
Where,
P
new
P
old
Sample
T
avg
T
sample
If the measurement condition change (for example, a range change in
automatic ranging), P
why the display update seems faster in automatic ranging.
To set the averaging time to 1 second:
Agilent 8163A/B, 8164A/B, and 8166A/B User's Guide, Fourth Edition
−47.000 dBm
−57.000 dBm
−67.000 dBm
x x x
T
sample
P = P 1 – ----------------- -
æ
new old
T
avg
is the new displayed result,
is the previously displayed result,
is the value read by the hardware,
is the averaging time, as set by the user, and
is the time the hardware takes to make a reading.
is reset and the averaging starts again. This is
old
How to Measure Power
Resolution
−90.000 dBm
0.001 nw
−100.000 dBm
0.1 pW
−110.000 dBm
0.01 pW
x x
T
sample
----------------- -
+ Sample
ö æ ö
T
ø ø
avg