Fluke 271 manual Effect of the output attenuator, Dc Offset Change * * By Output Level

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Getting Started Manual

Effect of the output attenuator

The instrument has an output attenuator with fixed steps of 20 dB. The attenuator follows the output stages so any dc offset added to the waveform is subject to the attenuator.

With the waveform amplitude set to 4 V p-p the attenuator is switched out; however if you adjust the output to (say)

0.4V p-p, 20 dB of attenuation is switched in. When this happens you will be warned that the dc offset has been changed.

Try it. Set the amplitude to 4 V p-p and the dc offset to +1.5 V.

Now change the amplitude by pressing AMPL, 0.4, V. The instrument will beep and you should see something like this for a few seconds:

**** WARNING 07 ****

* DC OFFSET CHANGE * * BY OUTPUT LEVEL *

********************

Then this:

PER =80.00000us

VhiZ=+4.00 Vpp 50Ω

DC=+1.50 V (+151.mV)

SYM=50.0% (50.0%)

The figure in brackets to the right of the programmed dc offset is the value which results from the application of 20 dB of attenuation. It may differ slightly from the calculated value (150 mV) because of the attenuator's saved calibration factors.

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