Q. Explain Radio and Television Broadcasting?

Radio (AM and FM) and television broadcasting are the most familiar forms of communication via analog transmission systems. The receiver most commonly used in AM radio broadcasting is the superheterodyne receiver, shown in Figure, which consists of a radio-frequency (RF) tuned amplifier, mixer, local oscillator, intermediate frequency (IF) amplifier, envelope detector, audio-frequency amplifier, and a loudspeaker. Tuning at the desired radio frequency f_c is achieved by a variable capacitor, which simultaneously tunes the RF amplifier and the frequency f_LO of the local oscillator. Every AM radio signal, in a superheterodyne receiver, is converted to a common IF frequency of f_IF = |f_c - f_LO| = 455 kHz, which allows the use of a single tuned IF amplifier for signals from any radio station in the frequency band. Matching the bandwidth of the transmitted signal, the IF amplifier is set to have a bandwidth of 10 kHz.