EXFO IQS-1700 High Performance Power Meter for IQS-500/600 - Manual (Page 59)

Measuring Power
High Performance Power Meter 51
Averaging Measurements
Averaging Measurements
When the averaging function is enabled on the IQS-1700 High Performance
Power Meter, the most recent measurement samples, for which you can
set the number, are used to compute an unweighted average. This average
is displayed as the measured value. The AVG marker will also be displayed
to the right of the value for the matching channel, indicating that averaging
is enabled.
Averaging can be done on a minimum of 2 and a maximum of 1000 points
(you can enter 1 as a value, but the averaging will be performed only on
that value and will be rather useless). The calculation uses watt as unit, but
the result will be converted into the unit you have selected for your
acquisition (W, W/W, dBm or dB) afterwards.
The formulas used to calculate measurement averaging depend on the
number of the current acquisition.
If n M, then
Where

n is the number of the current acquisition

M is the number of points to average (value you set)

x[n] is the current sample in watts

y[n] is the result of the present average in watts

y[n-1] is the value before the average in watts
y n  
1
M
----- x n    1
1
M
----- –
 
  y n 1
–    + =