The first two lectures.
I remember when i was a child that i was always questioning me about things around me . I grew up and i started to disassemble and riassemble everything that was mechanical or electronic like old computers or watch. Then i decided to enter at university. Unfortunately at the end of the most of the courses the questions are more than the answers, i always thought that the cause was the total lack of practical laboratories in my university in Italy.
The course of DISEÑO DE RADIO RECEPTORES is started exactly how i dreamed. Professor José Maria drew in the blackboard a typical block diagram of a communication system (one of those i saw many times in the books and i wrote many times in my notes), i always asked to myself how in the real world (with circuits, resistors, wires, transistors, ecc...) are made each block of those diagrams. This is the same question that José Maria asked to us. Very well, i hope that in this course i will able to answer to old (and new) questions.
The first chapter is REINVENTADO LA RADIO, we have to imagine that we are only experts of circuits theory, and we want to build up a radio (to communicate).
First of all we need to generate electromagnetic waves, so we have to build an antenna (the dipole is the most simple). The lenght of the dipole is very important and it's directly related at the wavelength (or at the frequency of interest). It's important to know that the same antenna used in transmission can be used in reception to capture the desired signal.
Build this dipole antenna can be very difficult in the real world for low frequencies and so we studied others types of antenna: monopole or ferrite coil.
We saw the laws of the radiating and receiving powers: they are not only formulas but each term has a exact physical meaning connected for example to the volume of a sphere, to the gain of an antenna (if is not isotropic) and to the distance from the transmitter to the receiver.
Nessun commento:
Posta un commento