6.9 How radio works 22 October 2015 What is this image? What other information can you get from it?

Aims Review knowledge of AC State the difference between AM and FM Describe how a simple radio works

Sending sounds by radio RF OscillatorModulatorAmplifier Microphone AF signal RF carrierModulated RF carrier

Sending sounds by radio AmplifierdemodulatorTuning circuit Loudspeaker AF signalModulated RF carrier

Radio gaga AF signal: varying voltage RF oscillator creates high frequency AC, this is the carrier AF signals modulate the RF waves RF wave is then amplified RF waves then generate a voltage in the aerial The tuning circuit decides which frequency of RF carrier to detect The demodulator then removes the carrier wave leaving on AF This is amplified and then converted to sound

AM and FM This is amplitude modulation or AM You can also use frequency modulation (FM) FM has less noise so this is better