Available online
Description
The programme examines two applications of adaptive systems; anequaliser on a telecommunications channel and a diversity reception radio microphone.
The programme examines two applications of adaptive systems; anequaliser on a telecommunications channel and a diversity reception radio microphone.
| Module code and title: | T321, Telecommunication systems |
|---|---|
| Item code: | T321; 07 |
| First transmission date: | 15-05-1976 |
| Published: | 1976 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:28 |
| + Show more... | |
| Producer: | Tony Jolly |
| Contributors: | David Crecraft; Graham Martin |
| Publisher: | BBC Open University |
| Keyword(s): | Digital filter; Diversity reception microphone; Equaliser; Modem; Phasor display |
| Footage description: | Shots of a phasor display of a high speed data modem. Glyn Martin introduces the programme. David Crecraft, with an animated diagram, discusses the ideal amplitude and delay characteristics of a telephone line. He then displays the characteristics of a typical telephone line on an animated graph and explains why equalisation is necessary. Crecraft tests the group delay characteristics of a telephone line simulator. He explains the experiment and displays the results on an oscilloscope screen. Crecraft discusses the results and then runs through the demonstration again. Crecraft uses a manual equaliser to equalise the simulated telephone line above. The result is displayed on an oscilloscope screen. Crecraft explains what is happening. Crecraft discusses the effect of filtering in automatic equalisers on data pulses sent down the line. He uses a block diagram of the system and waveforms of the line output signal made up of two adjacent pulses. Glyn Martin uses a special phasor display to show signal states which are built up from four to sixteen phasors as data rate is increased. David Crecraft demonstrates diversity reception in the adaptive radio microphone system. As part of the demonstration, Glyn Martin carries a VHF radio transmitter around the studio. The transmitter provides the radio microphone facility. An animated diagram helps to illustrate points made during the demonstration. |
| Master spool number: | 6HT/72037 |
| Production number: | 00525_5226 |
| Videofinder number: | 1348 |
| Available to public: | no |
