This example demonstrates co-simulation of a QAM system, with noise included in the subcircuit. The noise figure of the receiver's LNA is varied and the BER is simulated versus this noise figure.
The Co_sim_noise schematic shows the QAM transmit and receive sections as well as simulation controllers and BER measurement sinks. The RF downconverter is the subcircuit inside the blue box
QAM transmitter/receiver simulation setup
The data display shows the BER versus amplifier noise figure as well as the Q-channel input and output waveforms. There is a different output waveform for each value of the LNA's noise figure.
Q-channel input and output waveforms and BER versus amplifier noise figure; display page 2 (not shown) has the Q-channel output spectrum