Radio communication Radio wave

in order receive radio signals, instance am/fm radio stations, radio antenna must used. however, since antenna pick thousands of radio signals @ time, radio tuner necessary tune in particular signal. typically done via resonator (in simplest form, circuit capacitor, inductor, or crystal oscillator, many modern radios use phase locked loop systems). resonator configured resonate @ particular frequency, allowing tuner amplify sine waves @ radio frequency , ignore other sine waves. usually, either inductor or capacitor of resonator adjustable, allowing user change frequency @ resonates.