Keithley 2461 - Moving Average Filter; Setting up the Averaging Filter

Section
4: Source-measure considerations Model 2461 Interactive SourceMeter® Instrument
Reference Manual
4-24 2461-901-01 A/November 2015
Moving average filter
When the moving average filter is selected, the measurements are added to the stack continuously
on a first-in, first-out basis. As each measurement is made, the oldest measurement is removed from
the stack. A new averaged sample is produced using the new measurement and the data that is now
in the stack.
Note that when the moving average filter is first selected, the stack is empty. When the first
measurement is made, it is copied into all the stack locations to fill the stack. A true average is not
produced until the stack is filled with new measurements.
For example, if the filter size is four, the first measurement is copied to all four stack locations.
Therefore, (Reading1 + Reading1 + Reading1 + Reading1)/4. The display and remote interface
update after first reading. With each additional measurement, the average updates:
(Reading2 + Reading1 + Reading1 + Reading1)/4
(Reading3 + Reading2 + Reading1 + Reading1)/4
(Reading4 + Reading3 + Reading2 + Reading1)/4
Do not use the moving average filter when performing a sweep in which source levels are being
changed. You should always use a repeating average filter in this case.
Setting up the averaging filter
Using the front panel:
1. Press the MENU key.
2. Under Measure, select Calculations.
3. For Filter, select On to enable filtering.
4. Select Config.
5. For the Filter Type, select Moving or Repeat.
6. For the Filter Count, enter the number of measurements to be made for each averaged
measurement sample.
7. Select OK.
8. Select HOME to return to the Home screen to view the measurements with the filter applied.
Once the filter is set up, you can enable and disable the filter from the SETTINGS swipe screen.
When filtering is enabled, the FILT indicator on the Home screen is lit.
Using SCPI commands:
To set the averaging filters using SCPI commands, refer to the following command descriptions:
[:SENSe[1]]:<function>:AVERage:COUNt (on page 6-53)
[:SENSe[1]]:<function>:AVERage[:STATe] (on page 6-55)
[:SENSe[1]]:<function>:AVERage:TCONtrol (on page 6-56)
Using TSP commands:
To set the averaging filters using TSP commands, refer to the following command descriptions: