Lecture 3 - The sound of broadcasting
For many types of message the meaning is all that really matters. 'Message received and understood' is the criterion of good transmission.
Sound broadcasting, which started in this country 50 years ago, demands much more than this. Not only do we need to understand the spoken words but we want to be able to recognise the voice. Nor is it sufficient to be able to recognise the tune - we expect the music to sound realistic.
For high quality reproduction of speech and music we need to understand the causes and effects of all the relatively small distortions of the signal that can occur during its journey from the studio microphone to the loudspeaker in our home. One of the principal difficulties is that radio waves carrying different programmes can interfere with each other if the radio-frequency spectrum - the ether as we used to call it - gets overcrowded. A radio wave can 'carry' a signal in a number of different ways and we shall see that some ways offer advantages when the object is to avoid interference from other sources of radio wave.
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.