Signal vs Noise
Signal and noise are two terms used in electrical engineering and communications. Signal is a time or space varying quantity carrying some information, and noise is an unwanted effect on signal which reduces the visibility of that information. Signal to noise (S/N) ratio is a widely used parameter to measure the quality of signals. The higher the S/N ratio, better the signal in quality.
A signal is an information carrier. It is a time or space varying quantity and used to send information. Many things can be considered as signals. For example, pixels of an image, a written line of text, and color of the sky are all some sort of signals. However, electrical signals are the most studied and used type of signals.
Signals can be categorized as analog and digital. Analog signals can take any value, whereas in digital signals, it is restricted to certain values. Information content of a signal is an important parameter, and it is called the ‘entropy’. Usually signals are analyzed in frequency domain for the convenience.
Noise is an unwanted effect on signals. Noise is added on to signal due to many natural reasons as it travels through a medium. Noise can randomly fluctuate the value of signals, and it disturbs the process of revealing the information sent through a signal.
Noise can occur due to natural or artificial reasons. There are many types of noise such as thermal noise, shot noise, flicker noise, burst noise, and avalanche noise in electronics. White noise and Gaussian noise are statistically defined noise types. Some of the noise are unavoidable and only the effect of them on signals can be minimized.
Effect of noise on a signal is measured using a parameter known as signal to noise (S/N) ratio. If the S/N ratio is small, effect of the noise is higher. If the S/N ratio is less than one and very low, revealing the information held in the signal is difficult.
What is the difference between Signal and Noise?
1. Usually signal is a wanted part, and noise is an unwanted part,which should be eliminated.
2. For a signal to be high in quality, signal to noise ratio should be a high value
3. Noise is also a random signal that is added to the original signal.