OQPSK Align I & Q (Digital Demod)
Menu Path:
Default: Cleared
specifies whether to align the I and Q parts of the and trace data.
The parameter is only available when demodulation Format is set to Offset QPSK or Shaped OQPSK.
When is selected, the Q part of the and trace data is shifted by 1/2 symbol to line up the decision points of the I and Q parts of the waveform. Shifting the Q part of the waveform makes the constellation points better represent the error which contributes towards bit errors in coherent demodulation algorithms within a receiver.
Shifting the Q part of the signal by 1/2 symbol also lines up the zero crossings of the signal. This means the trajectory between decision points no longer represents the actual transmitted signal.
This parameter only affects the and trace data. and (which are computed directly from and will be different but their overall shape is not changed.
See Also
Half-Sine shaping (for OQPSK) (Digital Demod)
