Lecture 4 - Pictures with and without wires
Sending still black-and-white pictures over a telephone line or a radio link does not present any great difficulty - at least, not if we are prepared to wait a few minutes for the complete picture to be reconstructed at the receiving end. This is because the electric signal which describes the variations of light and shade does not have to change its value very rapidly.
Television is much more difficult and many problems had to be solved before it became possible to transmit over long distances clear black-and -white pictures of 1 live' scenes. One soon discovers that in order to reproduce on a television screen the sort of picture that we see on a cinema screen information has to be transmitted at an enormously high rate. The same rate of sending information, if used for telegraphy, would be sufficient to transmit the complete works of Shakespeare three times a second.
About the 1972 CHRISTMAS LECTURES
In his 1972 CHRISTMAS LECTURES, Geoffrey G Gouriet explores the past, present and future of radio communications, and the science that lies behind it.
Radio waves are all around us, continuously being produced and received through man-made devices enabling us to connect with each other and communicate information. Geoffrey Gouriet, through the course of six Lectures, takes us on a journey through history from the first telephone to the 'Viewphone' and with the aid of exciting demonstrations, he explains how devices in our house like the TV translate broadcasted signals into moving pictures.
Gouriet begins with an introduction to electromagnetic waves and the principle behind it as well as how electricity can be used to transmit information.
We then learn how we can get rid of the wires and transmit information through the 'ether' using radio waves and utilizing the layers of the Earth's atmosphere to reach distant locations; the basis of radio and TV broadcasting.
Finally, Gouriet demonstrates how TVs and radios work and how the broadcasted signal is translated. In his last lecture, he gives us a 'vision of the future' outlining how different technologies were currently (then) in development and he even sets up a live broadcast using small dishes from within the lecture theatre.