AM Radio Communication Systems essays

AM Radio Communication Systems essays The process of AM radio signal transmission requires low frequency audio signals to be radiated long distances. This is done by superimposing the low frequency audio signal on a high frequency carrier wave by the process of modulation. This section will describe what each section of the AM transmitter is and the function of it.. The microphone converts sound waves into electrical signals at a very low level (the audio frequency range of 20 Hz to 20 kHz). These signals are amplified by the modulator. The modulator is just an audio frequency amplifier that increases the output of the microphone to a useable level. This increased audio frequency is input into a modulation amplifier (This is some type of non linear device), along with the carrier frequency. The carrier frequency is generated by the RF (radio frequency) oscillator. This oscillator is required to be extremely stable regardless of age or temperature. The audio is superimposed onto the carrier by the modulation amplifier. The low power modulated carrier is boosted in amplitude by one or more the radio frequency power amplifier. The antenna produces an electromagnetic wave which is radiated into space. This signal will be received by the receiver. This section will describe the operation of the superheterodyne receiver. The design of the superheterodyne receiver uses a different approach that has eliminated the need for complex adjustment of the filter. The superheterodyne receiver uses a fixed filter and attempts to alter the desired input signal to the tuned frequency of the filter. There are low power signals from thousands of radio transmitters on many different frequencies. Because of all of these low level frequencies, a receiver must have very good selectivity (the ability to select one frequency while rejecting all others), and good sensitivity (the ability to receive a weak signal and amplify it to a useable level).These signals are inducing signal volt...