R&S AFQ100A Operating Manual page 154

R&S AFQ100A
Phase error
1401.3084.32
Effect of an identical offsets for both signal components:
Remote-control commands:
SOUR:IMP:OFFS:I 0.12FS
SOUR:IMP:OFFS:Q 0.10FS
The command sets an I/Q phase mismatch
90 deg.
An ideal I/Q modulator sets the phase angle to exactly 90 degrees.
With a phase error, the phase angle between the I and Q vector
deviates from the ideal 90 degrees, the amplitudes of both
components are of the same size. In the vector diagram, the
quadrature offset causes the coordinate system to shift.
A positive quadrature offset means a phase angle greater than 90
degrees:
4.43
Impairments Block
, i.e. a deviation from
E-3