Constellation (Trace Format)
A constellation diagram is like an IQ diagram but information is shown only at specified time intervals. The constellation diagram shows the IQ diagram only at points that correspond to the symbol clock times. These points are commonly referred to as detection decision-points and are called symbols. Constellation diagrams help identify such things as amplitude imbalance, quadrature error, or phase noise.
The trace format behaves like the trace format except the format ignores the setting and only displays the samples at the symbol locations (similar to = 1).
The constellation diagram is primarily a time-domain display. However, the format can be selected for frequency-domain data. In this case, the VSA displays the complex frequency domain values on an IQ plot which is similar to the IQ trace format but without the lines that connect the points.
In digital demodulation, the bits that correspond to each symbol location can be defined. For details, see sync and state definitions.
In the format, the VSA can display the location of ideal states using crosshairs or circles. For details, see ideal state.
Ideal States do not apply to composite time trace data for or demodulation.
