Keysight N9000B - IQ Offset Compensation

3 VMA Mode
3.1 Digital Demod Measurement
EVM Normalization Reference also affects the normalization value used for traces
wheormalize is turned on. Note that the normalization value used for traces differs
from the normalization value used for error summary metrics when EVM
Normalization Reference is set to Reference RMS.
These scalar results are normalized by the EVM Normalization Reference:
–
EVM
–
Mag Err
There are two possible values for EVM Normalization Reference:
Constellation
Maximum
(Default)
Sets the normalization value to the maximum constellation magnitude
For example, the normalization value would be the level of the corner point in a
16QAM constellation. For "cross-QAM" constellations (32QAM, 128QAM,
512QAM), the normalization value would be set to the magnitude of the outer
corners of a square that encompasses the constellation, even though the
constellation itself does not actually use the outer corners
Reference RMS Sets the normalization value to the RMS level of the IQ Reference symbol points
If the only impairment in the input signal is Additive White Gaussian Noise, using
Reference RMS will make the averaged EVM approach the inverse of the Signal-
to-Noise ratio of the signal. Using Reference RMS also makes it easier to
compare EVM values between signals of different modulation formats
Remote
Command
[:SENSe]:DDEMod:SEGMent1|…|6:COMPensate:NREFerence CMAXimum | RRMS
[:SENSe]:DDEMod:SEGMent1|…|6:COMPensate:NREFerence?
Example
:DDEM:SEGM1:COMP:NREF RRMS
:DDEM:SEGM1:COMP:NREF?
Couplings Reference RMS is only available for Custom IQ format and I/Q modulation formats with more than one
constellation magnitude level (16QAM, 32APSK, etc.)
Preset
CMAX
State Saved Yes
Range Constellation Maximum | Reference RMS
Backwards
Compatibility
SCPI
[:SENSe]:DDEMod:COMPensate:NREFerence
IQ Offset Compensation
Selects whether to compensate IQ Offset at parameter estimation and
compensation time prior to metrics like EVM calculation.
Remote Command
:CALCulate:DDEMod:SEGMent1|…|6:COMPensate:IQOFfset[:STATe] OFF | ON | 0 | 1
:CALCulate:DDEMod:SEGMent1|…|6:COMPensate:IQOFfset[:STATe]?
349 Vector Modulation Analyzer Mode User's &Programmer's Reference