Agilent Technologies 34410A, Руководство пользователя

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34410A/11A User’s Guide 109
Measurement Tutorial 4
Other Primary Measurement Functions
Frequency and Period Measurement Errors
The multimeter uses a reciprocal counting technique to measure frequency
and period. This method generates constant measurement resolution for
any input frequency. The multimeter's ac voltage measurement section
performs input signal conditioning. All frequency counters are susceptible
to errors when measuring low–voltage, low–frequency signals. The effects
of both internal noise and external noise pickup are critical when
measuring "slow" signals. The error is inversely proportional to frequency.
Measurement errors will also occur if you attempt to measure the
frequency (or period) of an input following a dc offset voltage change. You
must allow the multimeter's input dc blocking capacitor to fully settle
before making frequency measurements.
DC Current Measurements
When you connect the multimeter in series with a test circuit to measure
current, a measurement error is introduced. The error is caused by the
multimeter's series burden voltage. A voltage is developed across the
wiring resistance and current shunt resistance of the multimeter, as
shown below.