Agilent 33120A User's Guide

Chapter 4 Remote Interface ReferenceUsing the APPLy CommandDC Offset Voltageœ For the offset parameter of the APPLy command, you can substitute“MINimum”, “MAXimum”, or “DEFault” in place of a specific value forthe parameter. MIN selects the smallest dc offset voltage for theselected function (0 volts). MAX selects the largest offset for theselected function. The default offset voltage is 0 volts for all functions.œ You can set the offset to a positive or negative number with therestrictions shown below. If the specified offset voltage is not valid,the function generator will automatically adjust it to the maximumdc voltage allowed with the present amplitude. (Vmax is the maximumpeak-to-peak amplitude for the selected output termination; Vpp isthe output amplitude in volts peak-to-peak.) From the remote interface,a -221, “Settings conflict” error is generated and the offset is adjusted.Ô Voffset Ô +Vpp2 ˆ Vmax and Ô Voffset Ô ˆ 2 x Vppœ DC Offset and Output Termination: The offset voltage is automaticallyadjusted (and no error is generated) if you change theoutput termination. For example, if you set the offset to 100 mVdc andthen change the termination from 50 ohms to “high impedance”,the displayed offset will double to 200 mVdc. If you change from “highimpedance” to 50 ohms, the displayed offset will drop in half.See “Output Termination” on page 65 for more information.œ For arbitrary waveforms, the Offset annunciator will turn on if thewaveform data has an inherent offset present (if the average is notequal to zero). The function generator calculates the average of thedata points and compares the average to zero volts. If the average isnot within two DAC (Digital-to-Analog Converter) counts of zero volts,the Offset annunciator turns on.œ For dc volts, the output level is actually controlled by setting theoffset voltage. You can set the dc voltage to any value between –5 Vdcinto 50 ohms or –10 Vdc into an open circuit.142