Error Vector Spec (802.11b/g DSSS/CCK/PBCC)

When 802.11b/g DSSS Direct sequence spread spectrum. The data transmission scheme (sometimes referred to as a "'modulation" scheme) used in 802.11b WLANs. DSSS uses a radio transmitter operating at a fixed centre frequency, but using a relatively broad range of frequencies, to spread data transmissions over a fixed range of the frequency band. 802.11a and 802.11g (when not operating in 802.11b mode) use Orthogonal Frequency Division Multiplexing (OFDM)./CCK complementary code keying/PBCC packet binary convolutional code Demodulation is enabled, the Error Vector Spec trace shows the spectrum of the Error Vector Time trace. In other words, the VSA derives the Error Vector Time trace, then windows and FFTs this trace to produce the Error Vector Spec trace.

The VSA's demodulator removes carrier-frequency error. Therefore, in the Error Vector Spect display, add the carrier-frequency error to marker readouts to obtain exact frequency information. The carrier-frequency error (Freq Err) is shown in the symbol table.

The center frequency and span for Error Vector Spect is identical to IQ Meas Spectrum. For details, see IQ Measured Time.