Available online
Description
The programme demonstrates three types of modulation: full amplitude, double sideband suppressed carrier, and single sideband modulation. An explanation of a stereo broadcasting system is also given.
The programme demonstrates three types of modulation: full amplitude, double sideband suppressed carrier, and single sideband modulation. An explanation of a stereo broadcasting system is also given.
| Module code and title: | T321, Telecommunication systems |
|---|---|
| Item code: | T321; 02 |
| First transmission date: | 28-02-1976 |
| Published: | 1976 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:23:00 |
| + Show more... | |
| Producer: | David Saunders |
| Contributors: | Glyn Martin; Chris Pinches |
| Publisher: | BBC Open University |
| Keyword(s): | De-modulation; Double sideband suppressed carrier modulation; DSBSC; Envelope detector; Full amplitude modulation; Single sideband modulation; Spectrum analyser; Stereo radio |
| Footage description: | Glyn Martin introduces the programme. He begins by demonstrating a full amplitude modulation. Martin goes on to demonstrate the demodulation of the message signal by use of an envelope detector. Chris Pinches points out and explains the calibrations on the screen of the spectrum analyser. He goes on to examine an amplitude modulated wave on this instrument. Pinches examines a double sideband suppressed carrier modulation on the spectrum analyser and then a single side band transmission. Glyn Martin looks at the wave forms of the above two types of modulation on an oscilloscope. Chris Pinches, with the aid of video animation explains the action of a synchronous detector (product detector) in demodulating double side band and single side band suppressed carrier signals. He points out the effect of phase errors in the local oscillator. Glyn Martin explains briefly and in general terms how a stereo system works, particularly how its compatibility with mono transmission is ensured. An animated diagram illustrates points made. Martin goes on to explain and demonstrate, on the spectrum analyser, how a stereo multiplex signal for stereo radio transmission is formed. Glyn Martin, with the aid of an animated diagram explains how a stereo radio receiver demodulates the F.M. signal. |
| Master spool number: | 6HT/71938 |
| Production number: | 00525_5221 |
| Videofinder number: | 1343 |
| Available to public: | no |
