AM Radio Communication Systems

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

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The superheterodyne receiver uses a fixed filter and attempts to alter the desired input signal to the tuned frequency of the filter. Unfortunately, these multiple stage filters can be very difficult tune into the desired frequency.

The power level is increased sufficiently to drive the loudspeaker by the power amplifier. First, the information being sent is always transformed into electrical signal through the appropriate converter. 1-c having constant amplitude, and their frequency being changed in accordance with the actual value of LF signal from the microphone. The antenna converts the electro-magnetic waves into voltages used by the receiver. This, naturally, is the way it would be in ideal case.

The mixer and oscillator form a FREQUENCY CHANGER circuit.

Common topics in this essay:
Linking RF, GAIN CONTROL, Operation Transmitters, Superheterodyne Receiver, FREQUENCY CHANGER, TV CRT, lf signal, superheterodyne receiver, input signal, low frequency, local oscillator, intermediate frequency, rf filter, audio signal, block diagram, radio station, automatic gain control, effect lf signal, transmitter effect lf, block diagram pic21, low frequency audio,

Approximate Word count = 1544
Approximate Pages = 6 (250 words per page double spaced)

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