This m-file simulates the operation of the heterodyne section and

demodulating section of a garden variety AM receiver. An array is created

that represents the superposition of three separate RF carriers, each

modulated at a different audio frequency. This is the kind of signal that

could be expected at the output of the LNA. This signal is multiplied by

a local oscillator, passed though an IF filter, and demodulated using a

simple envelope detector (half-wave rectifier and single pole LPF). Some

plots are created at the end to show the signal at various locations in

the receiver.-　This m-file simulates the operation of the heterodyne section and

　demodulating section of a garden variety AM receiver. An array is created

　that represents the superposition of three separate RF carriers, each

　modulated at a different audio frequency. This is the kind of signal that

　could be expected at the output of the LNA. This signal is multiplied by

　a local oscillator, passed though an IF filter, and demodulated using a

　simple envelope detector (half-wave rectifier and single pole LPF). Some

　plots are created at the end to show the signal at various locations in

　the receiver.