Ac Filter; Other Primary Measurement Functions; Frequency Measurement Errors - DATATEC EDU34450A Guia Del Usuario

AC Filter

The instrument's AC voltage and AC current functions implement three low-frequency comb filters. These filters
allow you to trade-off minimum measured frequency for faster reading speed. The "SLOW" mode filter cut-off at 2
Hz and useful for frequencies above 20 Hz. The "MEDIUM" filter cut-off at 20 Hz and useful for frequencies above
200 Hz. The "FAST" filter cut-off at 200 Hz and useful for frequencies above 1 kHz.
DC current measurements
When you connect the instrument in series with a test circuit to measure current, a measurement error is
introduced. The error is caused by the instrument's series burden voltage. A voltage is developed across the wiring
resistance and current shunt resistance of the instrument, as shown below.

Other Primary Measurement Functions

Frequency Measurement Errors

The instrument uses a reciprocal counting technique to measure frequency. This method generates constant
measurement resolution for any input frequency. 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 also occur if you
attempt to measure the frequency of an input following a DC offset voltage change. You must allow the instrument's
input to fully settle before making frequency measurements.
108 Keysight EDU34450A User's Guide