8163A/B, 8164A/B, 8166A/B User’s Guide 103Power Measurement 3To set the calibration offset to 40.000 dB:1 Move to the Power Meter channel and press the [Details] softkey.2 Move to the [Cal] parameter and press Enter.3 Enter 40.000 and press Enter.How to Set the Reference LevelHow to Input a Reference LeveldB results are shown relative to a reference level. The [Ref] parameter setsthe reference level. Setting, or changing, the reference only affects resultsthat are displayed in dB.The reference level is displayed in units of dBm or Watts. Depending onwhich is selected the following equations are used to calculate the powerlevel in dB:P display(dB) = P measured (dBm) - REF(dBm)orWhere,P display is the displayed relative power,P measured is the absolute power level (see How to Set the Calibration Offseton page 102), andREF is the reference level.You can choose the units for the reference using the Power Unit softkey. Ifyou choose dB, the power value changes to dB and the displayedreference level changes to dBm.To set the reference level to 10 mW:1 Move to the Power Meter channel and press the [Details] softkey.2 Move to the [Ref] parameter and press the [Power Unit] softkey.3 Move to <W> and press Enter twice.4 Change the units to mW using the [Unit+] and [Unit-] softkeys.5 Enter 10.000 and press Enter.P display dB( ) 10 P measured W( )REF W( )-----------------------------------log=
