Keysight U1251B Guia Del Usuario página 154

6 Performance Tests and Calibration
Test Considerations
Long test leads can also act as antennas which may pick up AC signals.
For optimum performance, all procedures should comply with the following
recommendations:
– Ensure that the calibration ambient temperature is stable and is between 18 °C
– Ensure that the ambient relative humidity is less than 80%.
– Allow a warm-up period of five minutes.
– Use shielded twisted pair PTFE-insulated cables to reduce settling and noise
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and 28 °C. Ideally the calibration should be performed at 23 °C ± 1 °C.
errors. Keep the input cables as short as possible.
Keysight U1251B and U1252B User's and Service Guide