SPECIAL TOPIC-DEMODULATION

This a side topic on DEMODULATION, PARTICULARLY OF AM SIGNALS. bELOW ARE THREE WAYS AND NOT NECESSARILY THE ONLY WAYS. 1. DIODE DETECTION The most common. If we look at the original "Crystal Set" receiver, a diode converts the RF AC to DC. and sine the AC is AM, the converted DC fluctuates in accordance to the signal strength. In Super Heterodyne radios , this technique is used. 2. Current/Voltage sensing In regenerative receivers, a low power oscillator is the RX. When a signal of the same frequency appears, the current draw on this oscillator changes. It can be sensed by putting a transformer in series to the supply line. A secondary winding senses the fluctuating current draw. A cap straight to the collector can also sense the voltage changes. 3. Direct Conversion A mixer mixes the incoming signal with a local OSC where the differential is within the human hearing.