Agilent Technologies X Series Manual page 416

Input/Output
the signal from the Q input port appears as the "I" data. Another situation where the I and Q data do not
necessarily correspond directly to the I and Q inputs is when the center frequency is non-zero. The
digital processing involved in the tuning is a complex operation. This will result in I Only data appearing
as both "I" and "Q" data, the same as that signal would appear if seen through the RF input port.
I/Q Path
Selects which I/Q input channels are active. The LED next to each I/Q input port will be on when that
port is active.
The analysis bandwidth for each channel is the same as that of the instrument. So, for example, the base
N9020A has a bandwidth of 10 MHz. With I/Q input the I and Q channels would each have an analysis
bandwidth of 10 MHz, giving 20 MHz of bandwidth when the I/Q Path is I+jQ. With option B25, the
available bandwidth becomes 25 MHz, giving 25 MHz each to I and Q and 50 MHz to I+jQ.
I/Q voltage to power conversion processing is dependent on the I/Q Path selected.
• With I+jQ input we know that the input signal may not be symmetrical about 0 Hz, because it has a
complex component. Therefore, above 0 Hz only the positive frequency information is displayed, and
below 0 Hz only the negative frequency information is displayed.
• With all other Input Path selections, the input signal has no complex component and therefore is
always symmetrical about 0 Hz. In this case, by convention, the power conversion shows the
combined voltage for both the positive and negative frequencies. The information displayed below 0
Hz is the mirror of the information displayed above 0 Hz. This results in a power reading 6.02 dB
higher (for both) than would be seen with only the positive frequency voltage. Note also that, in this
case the real signal may have complex modulation embedded in it, but that must be recovered by
further signal processing.
Key Path
Remote Command
Example
Notes
Preset
State Saved
Range
Readback Text
Initial S/W Revision
Remote Command
416
Input/Output, I/Q
[:SENSe]:FEED:IQ:TYPE IQ|IONLy|QONLy|INDependent
[:SENSe]:FEED:IQ:TYPE?
Set the input to be both the I and Q channels, combined as I + j * Q.
FEED:IQ:TYPE IQ
The Independent I and Q selection is only available in GPVSA
IQ
Yes
This is unaffected by a Preset but is set to the default value on a "Restore
Input/Output Defaults" or "Restore System Defaults->All"
I+jQ | I Only | Q Only | Independent I and Q
I+jQ | I Only | Q Only | Ind I/Q
Prior to A.02.00
:INPut[1]:IQ:TYPE IQ|I|Q
:INPut[1]:IQ:TYPE?