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The receiver of an AM radio is made of three basic parts; Antenna, Mixer and Oscillator. The antenna is obviously a very important part of the receiver. This is where the signal enters the radio. The frequency passing through the antenna creates a small voltage (V=IR) which drives the circuit. Within the receiver the radio wave at the antenna is amplified and then mixed with the local oscillator to produce the Intermediate Frequency which is the next stage. The mixeroscillator stage contains a transistor which is a key component in amplification. This transistor not only amplifies the signal but simultaneously oscillates at a frequency 455K Hz above the desired radio station frequency. So to calculate the frequency the oscillator operates at the frequency of 455K Hz can be added to the frequency of radio station seen on the dial of the radio. The following formula defines this: FO (Freq. of oscillator) + Fi (Freq. of Intelligence). The frequency of the intelligence is the frequency that is transmitted by the radio station. The antenna and the oscillator coils have resonant circuits that change when the radio is tuned for different stations. Again these resonant circuits act as filters to filter out and pass the desired frequency and reject the frequencies of the other stations.
Approximate Word count = 805
Approximate Pages = 3.2
(250 words per page double spaced)
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