Rigol DM858 - Application of the Analog Filter

At high frequencies, the additional loading error is:
s
R
: source resistance
F
: input frequency
in
C
: input capacitance (100pF) plus test lead capacitance
8.4 Application of the Analog Filter
The analog filter of DM858/DM858E can be used to reduce the impact of the AC
component in DC measurement. For most measurements, the filter is not necessary,
but sometimes it can be used to improve the DC measurement. For example, if the
DC source under test has a big AC ripple, the analog filter can be used to reduce it.
The analog filter cannot be used to filter the internal noise of the multimeter. It does
not work for open-circuit in DCI measurement, short-circuit in DCV measurement or
in measurement of the output from a precise DC calibrator. If used, it may result in
extra noise and large reading offset. To reduce the offset, the multimeter should be
cleared under the selected range and reading speed when using the analog filter. If
you cannot clear the multimeter, additional errors may occur in the measured results,
as shown in the following tables. For ranges and reading speeds not specified in the
table, the generated additional analog filter error can be omitted.
NOTE
By default, the analog filter of DM858/DM858E is enabled. You are not allowed to disable the
filter.
Measurement Tutorial
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