Error Vector Spec (1xEVDO)

When 1xEV-DO Demodulation is enabled, the Error Vector Spec trace data shows the spectrum of the Error Vector Time trace data. In other words, the VSA derives the composite Error Vector Time trace data, then windows and FFTs the data to produce the composite Error Vector Spectrum trace data.

Composite, forward link, trace data results are computed from the first measured slot. Composite, reverse link, trace data results are computed from the first measured half (0.5) slot. The and parameters have no effect on this measurement.

Marker Frequency Correction

The VSA's demodulator removes carrier-frequency error. Therefore, in the composite error vector spectrum display, add the carrier-frequency error to marker readouts to obtain exact frequency information. The carrier-frequency error (Freq Err) is shown in the Composite Error Summary trace data.

For forward link measurements, the Time Division nature of the signal produces non contiguous composite time data when specifying an Analysis Channel. To include the entire slot, and therefore have useful FFT Fast Fourier Transform: A mathematical operation performed on a time-domain signal to yield the individual spectral components that constitute the signal. See Spectrum. information, select the Combine TDM channels for composite results parameter.