Noise In Electrical Circuits, And The
Need For Reduction Of Noise
1. Noise in Electrical Circuits,
and The Need for Reduction of Noise.
Electronic components are basically made up of materials
that contain electrical charges. These electrical charges
are built due to electrons movements within the component.
Due to quantum nature of these electrons, an electrical
component produces noise at temperatures other than absolute
zero (00 K). Due to this fundamental nature of
materials to induce noise, it is impossible to remove noise
completely from an electrical circuit at room temperatures
(or the temperatures at which it operates). In other words,
material properties, thermal fluctuations, discreteness
of electrical charges, and junction temperatures are the
primary cause of noise
Why do we want to remove or contain the noise in an electrical
circuit? The reasons for reducing noise may be any of the
- To improve sensitivity of the circuit to detect
desired signals in a receiver.
- To reduce harmonic content and phase noise in a
- To improve output signal to noise ratio.
For example, take satellite TV. The signals your antenna
dish receives are of the order of -100dBm
Note: 1 mW (1X10-3 W) = 0dBm,
1 mW(1X10-6W) = -30dBm and so on.
To receive a signal of this magnitude, the noise levels
should be comfortably below -100dBm. This requires careful
design and manufacture of electrical components (both active
and passive), and assemblies.