Down-conversion and Demodulation of AM Radio Waves Using a Stanford Research Systems SR770

This experiment utilized a Stanford Research Systems SR770 instrument and a TeachSpin ‘Electronic Modules’ instrument box to study the down-conversion and demodulation of AM radio waves. In this experiment, local AM radio stations were located by finding their frequencies, and different methods of demodulation (envelope detection, heterodyne to ‘zero beat,’ and product detection) were used to observe effects such as motorboating, unwanted cyclic variation of output voltage that produces a sound similar to an idling motorboat engine.