157Using Option BBA Baseband I/Q InputsBaseband I/Q measurement overviewBaseband I/Q measurement overviewThe Baseband I/Q functionality is a hardware option, Option BBA. If the option isnot installed in the instrument, the I/Q functionality cannot be enabled.The Baseband I/Q option provides four input ports and one Calibration Output port.The input ports are I, I-bar, Q, and Q-bar. The I and I-bar together compose the Ichannel and the Q and Q-bar together compose the Q channel. Each channel has twomodes of operation:The system supports a variety of input passive probes as well as the Keysight 1153Aactive differential probe using the InfiniMax probe interface.NOTE To avoid duplication, this section describes only the details unique to using thebaseband I/Q inputs. For generic measurement details, refer to the previous “MakingMeasurements” sections.To make measurements using baseband I/Q Inputs, make the following selections:Mode DescriptionSingle Ended(unbalanced)In this mode, only the main port (I or Q) is used and thecomplementary ports (I-bar or Q-bar) is ignored. The I and Q portsare in single-ended mode when Differential “Off” is selected.Differential(balanced)In this mode, both main and complementary ports are used. Toactivate this mode, select Differential “On” from the I and Q Setupsoftkey menus.Step Notes1 Select measurement. Select a measurement that supports baseband I/Q inputs.2 Select the I/Q Path Press Input/Output, I/Q, I/Q Path.Select from the choices present on the screen. The pathselected is shown at the top of the measurement screen.3 Select the appropriatecircuit location andprobe(s) formeasurements.For details see ““Selecting input probes for basebandmeasurements” on page 223” in the Conceptschapter.4 Select baseband I/Qinput connectors.
