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NOISE IN COMMUNICATIONS PART I INTRODUCTION 1. Noise in communication systems originates both in the channel and in the communication equipment. 2. Noise consists of undesired, usually random, variations that interfere with the desired signals and inhibit communication. 3. Noise cannot be avoided completely, but its effect can be reduced. 4. How can we reduce noise in communication circuits? a) reducing the signal bandwidth b) increasing the transmitter power c) using low-noise amplifiers for weak signals 5. What are the two types of noise? a) Internal noise, which originates within the communication equipment b) External noise, which is the property of the channel EXTERNAL NOISE 1. “Static” that afflicts AM radio broadcasting during thunderstorms 2. Interference from automobile ignition systems is another problem. 3. Domestic and industrial electrical equipment, from light dimmers to vacuum cleaners to computers, can also cause objectionable noise. 4. Noise is produced by the sun and other stars. 5. Describe the three major types of External Noise! a) Equipment Noise i) Noise is generated by equipment that produces sparks. Examples include automobile engines and electric motor with brushes. ii) Any fast rise-time voltage or current can also generate interference, even without arcing. Light dimmers and computers fall into this category.
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iii) Noise of this type has a broad frequency spectrum, but energy is not equally distributed over the frequency range.
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