Keithley 4200A-SCS Reference Manual page 354

Model 4200A-SCS Parameter Analyzer Reference Manual
Filter Factor
To reduce measurement noise, each 4200A-SCS applies filtering, which may include averaging of
multiple readings to make one measurement. The Filter Factor is fixed for Fast, Normal, and Quiet
speeds. If you select the Custom Speed mode, you can type a Filter Factor of 0 to 100.
The default Filter Factor settings are listed in the following table.
Speed Mode
Fast
Normal
Quiet
Custom
When typing a custom Filter Factor, consider the following:
•
A Filter Factor of 1 specifies a normal level of filtering.
•
As a rule of thumb, doubling the Filter Factor halves the measurement noise.
•
A Filter Factor of 0 nullifies the SMU internal filtering.
When the Filter Factor and Delay Factor are set to zero, the internal pre-programmed values are
ignored.
Auto A/D Aperture
When Auto A/D Aperture is selected, the instrument picks the optimum A/D conversion time for most
normal measurements.
A/D Aperture Time
If Custom Speed is selected and Auto A/D Aperture is cleared, you can specify the A/D converter
integration time that is used to measure a signal. Each measured reading by a SMU is the result of
one or more A/D (analog-to-digital) conversions. A short integration time for each A/D conversion
results in a relatively fast measurement speed with increased noise. A long integration time results in
a relatively low-noise reading at a relatively low speed.
The integration time setting is based on the number of power line cycles (NPLCs). For 60 Hz line
power, 1.0 PLC = 16.67 ms (1/60). For 50 Hz line power, 1.0 PLC = 20 ms (1/50).
4200A-901-01 Rev. C / February 2017
Filter Factor
0.2
1
3
0 to 100
Section 6: Clarius
6-85