Chan Error Vector Time (TD-SCDMA)
When TD-SCDMA Demodulation is enabled, the
trace data shows the time domain error vector trace data results for the specified code channel and code layer ( ). trace data is the computed error vector between corresponding symbol points in the I/Q measured and I/Q reference signals. View the data results as Error Vector Magnitude, Error Vector Phase, only the I component or only the Q component (see Trace Data Formats below).
If normalization is OFF, the VSA shows the instantaneous magnitude for each point. If normalization is ON, the VSA shows the error vector as a percentage (see Normalize IQ Traces for an explanation of how this percentage is derived).
Trace Data Formats
It is important to remember that the
trace is a time record made up of complex, time-domain data. Each point in the time record has two components: I and Q. To make sense of the data, you must select an appropriate trace data format ( drop- down list).-
EVM (Error Vector Magnitude).
: Shows the -
: Shows the I component of the error vector.
-
Imag(Q) : Shows the Q component of the error vector.
-
Wrap Phase: Shows the Error Vector Phase error.
For example, to see the error-vector magnitude, select the
trace format ( ). Selecting Linear Mag computes the square root of the sum of the squares for each complex pair of points in the time record, which is the error-vector magnitude (EVM):
See Also