Why do I have to calibrate my measurements?  Isn’t the equipment calibrated?

Yes the devices are calibrated, however for accurate results you still need to calibrate the measurement itself.  The purpose of the calibration is to eliminate any influences caused by the probes or other cabling.  The calibration nulls any errors in gain or in phase.  The calibration is very simple.  Fr gain measurements connect the two probes to the same point in the circuit and perform a THRU calibration.  For impedance measurements it is important to perform three calibrations – Open Short and Load.  RF engineers are very used to performing this calibration while most analog engineers are not.  This calibration series removes all effects of the cables and wires for accurate measurements.  See the Bode 100 user manual for additional information regarding these settings.