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Understanding AWR .emz Files

Design Notes

Creating a Source Signal with "Burst" Modulation

This project illustrates how to create a "burst" modulated source signal by combining a carrier with a much lower frequency square wave as a modulating signal.

The Global Definitions window contains the following equations:

Fc defines the RF carrier frequency.

t is an array of time values used to calculate the signal.

Vt defines the RF carrier using the standard V(t) = cos(wt) definition. A0 - A3 define the time points where the square wave changes state to modulate the RF carrier.

Vc simply multiples the two signals (the square wave is achieved by summing the A0 - A3 terms), producing the burst pattern shown in the graph.

The project frequency is set low, 50MHz in this case. Experiment with this value to see the effects on the signal. Also, the number of harmonics must be increased significantly in order to produce the full waveform. In this case, 128 harmonics are used. Experiment with this setting as well to see the effects.

In general, you should adjust all parameter values and monitor the results to fully understand how to configure this approach to your specific requirements.

Schematic - Chirp

Graph - Chirp