I would like to know what is the Common Mode Rejection at 20kHz in DC mesurement of the 34410A in dB.
The 34410A is mesuring a tension on a shunt and it's possible that I have noise at a frequency of 20kHz.
Thank you for your help,
The 34410A is an integrating DMM which has very high Common Mode Noise rejection at all frequencies above the power line frequency. It is only specified for 60 Hz or 50 Hz for which it is 140 dB. You can optimize the rejection at 20 kHz by setting the integration aperture to a multiple of the 20 kHz period. A 50 ms aperture will give you very high rejection. You can't do this from the front panel. You have to enable the aperture setting with the [SENSe:]VOLTage:DC:APERture:ENABled On command and set it with the [SENSe:VOLTage:DC:APERture <seconds> command over the bus.
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