N5161A/62A/81A/82A/83A MXG Signal Generators User's Guide

Custom Digital Modulation (Option 431)Differential Encoding1st1st Symbol3rd Symbol5th Symbol2ndData = 0011100001{{{{{2nd Symbol4th Symbol3rd5th4thData Value00011011Symbol Table Offset+1–1+2+0As you can see from the previous illustration, the 1st and 4th symbols, having the same data value(00), produce the same state transition (forward 1 state). In differential encoding, symbol values donot define location; they define the direction and distance of a transition through the I/Q State Map.Using Differential EncodingThe signal generator’s Differential State Map table editor enables you to modify the differentialstate map associated with user–defined I/Q and user–defined FSK modulations. In this procedure,you create a user–defined I/Q modulation and then configure, activate, and apply differentialencoding to the user–defined modulation. For more information, see “Differential Encoding” onpage 287.Configuring User–Defined I/Q Modulation1. Press Preset.2. Perform the following keypress sequence required for your format type.For Custom FormatPress Mode > ARB Custom Modulation > Single Carrier Setup > Modulation Type > Define User I/Q >More 1 of 2 > Load Default I/Q Map > QAM > 4QAMAgilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide 291