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Apply Phase/Frequency Offset to QAM Modulated Signal

The model applies phase and frequency offsets to a 16-ary quadrature amplitude modulation (16-QAM) signal. The Phase/Frequency Offset block applies phase and frequency offsets to the input signal based on parameter settings specified in the Model Parameters block. The effects of updating the offset settings are illustrated by constellation diagrams of a 16-QAM signal.

This constellation diagram shows the 16-QAM constellation with no phase or frequency offset impairing the modulated signal. The simulation configuration has these settings.

Modulation order: 16
Sample time: 1.00e-03
Phase Offset (deg): 0.00
Frequency Offset (Hz): 0.00

A phase offset impairs each point in the constellation, causing a rotation in the counterclockwise direction for a positive phase offset. The constellation shows the signal impaired by these settings.

Phase Offset (deg): 20.00
Frequency Offset (Hz): 0.00

A frequency offset changes the angles of points in the constellation linearly over time, causing points in the constellation to shift radially in the counterclockwise direction for a positive frequency offset. Although the points are radially shifted, their magnitude is unchanged. The constellation shows the signal impaired by these settings.

Phase Offset (deg): 0.00
Frequency Offset (Hz): 0.50

Apply both phase and frequency offset. The constellation shows the signal impaired by these settings.

Phase Offset (deg): 20.00
Frequency Offset (Hz): 0.50