Agilent Technologies N5171B Command Reference Manual page 68

Basic Function Commands
Digital Modulation Subsystem—N5172B/82B ([:SOURce])
OFF (0) This choice disables the internal I/Q modulator. You can turn off the I/Q with this
choice even though a digital format is enabled. With this configuration, the RF
output signal will not be modulated, but the I/Q signals may be present at the
rear panel I and Q outputs depending on the rear panel output selection.
*RST 0
I/Q Off On
Key Entry
38 Agilent X-Series Signal Generators SCPI Command Reference