External Noise

How to reduce external noise ?
Ans) By locating the receivers at far waway places.
Now what is external noise?

• it is the Atmospheric Noise < 30 MHz ( it is very little in VHF and above.)


• it is Extra terrestrial noise 8 MHz to 1.49 Mhz ( e. g. solar noise, not much of it penetrates below 20 Mhz, penetrates down ionosphere )


• it is Industrail Noise 1 to 600 MHz

Receieved Noise increases as the receiver BW increases.

A note on frequencies and bands

HF 3 to 30 MHz
VHF 5 to 200 MHz
UHF 500 to 1000 MHz

And now its about bands ( not rock ! ) all frequencies in GHz

L S C X Ku K Ka V
1-2 2-4 4-8 8-12 12-18 18-27 27-40 40-80

as we move from L --------> V, PMPO decreases.

Integrated Circuits ( IC s )

Linear, digital and Microwave are three type of ICs.

Further, they are of Monolithic, Film and Hybrid.

Monolithic :- They have the disadvantage that:- 1. Range of element values, 2. tolerance variation of passive components ( 10- 30 % )

Film type ICs are of two types:- Thin ( deposion of conductive films) and Thick( deposition of resistive film). They have better tolerance.

Hybrid ICs are mix of Monolithic and film. Active comopnets include diffused transistors and diodes. Passive components are of thin film type.

Steps of IC manufactoring:-

• Material Preparation


• Surface Passivation


• Photolithography


• Junction Formation ( By diffusion or by ion implantation )


• Film deposition.