Agilent Technologies X Series Manual page 414

Input/Output
Notes
Initial S/W Revision
Baseband I/Q (Option BBA)
The Baseband I/Q functionality is a hardware option. It is option BBA. If the option is not installed, none
of the I/Q functionality is enabled.
The Baseband I/Q has four input ports and one output port. The input ports are I, I-bar, Q, and Q-bar. The
I and I-bar together compose the I channel and the Q and Q-bar together compose the Q channel. Each
channel has two modes of operation, Single-Ended (also called "unbalanced") and Differential Input
(also called "balanced"). When in Single-Ended operation, only the main port (I or Q) is used and the
complementary port (I-bar or Q-bar) is ignored. When in Differential Input mode, both main and
complementary ports are used.
The input settings (range, attenuation, skew, impedance, external gain) apply to the channels, not the
individual ports.
The system supports a variety of 1 MΩ input passive probes as well as the Agilent 113x Series active
differential probes using the Infinimax probe interface.
The Agilent 113x Series active probes can be used for both single ended and differential measurements.
In either case a single connection is made for each channel (on either the I or Q input). The input is
automatically configured to 50 Ω single ended and the probe power is supplied through the Infinimax
interface. The probe can be configured for a variety of input coupling and low frequency rejection
modes. In addition, a wide range of offset voltages and probe attenuation accessories are supported at the
probe interface. The active probe has the advantage that it does not significantly load the circuit under
test, even with unity gain probing.
With passive 1 MΩ probes, the probe will introduce a capacitive load on the circuit, unless higher
attenuation is used at the probe interface. Higher attenuation reduces the signal level and degrades the
signal-to-noise-ratio of the measurement. Passive probes are available with a variety of attenuation
values for a moderate cost. Most Agilent passive probes can be automatically identified by the system,
setting the input impedance setting required as well as the nominal attenuation. For single ended
measurements a single probe is used for each channel. Other passive probes can by used, with the
attenuation and impedance settings configured manually.
414
The parameters IQ|IONLy|QONLy are only supported for backwards
compatibility The E44406 SCPI has the following that corresponds to
FEED:IQ:TYPE for X-Series.
[:SENSe]:FEED IQ|IONLy|QONLy
[:SENSe]:FEED?
[:SENSe]:FEED IQ will set the I/Q path to IQ
[:SENSe]:FEED IONLy will set the I/Q path to I Only
[:SENSe]:FEED QONLy will set the I/Q path to QOnly
[:SENSe]:FEED? will not be backward compatible.
The query [:SENSe]:FEED? will always returns AIQ whatever the type of
legacy parameters IQ|IONLy|QONLy has been used.
Prior to A.02.00