Available online
Description
The programme tries to demonstrate the responses of various types of filters and their transfer characteristics, and to introduce the phasor representation of filter response.
The programme tries to demonstrate the responses of various types of filters and their transfer characteristics, and to introduce the phasor representation of filter response.
| Module code and title: | T321, Telecommunication systems |
|---|---|
| Item code: | T321; 01 |
| First transmission date: | 14-02-1976 |
| Published: | 1976 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:00 |
| + Show more... | |
| Producer: | David Saunders |
| Contributors: | David Crecraft; Gaby Smol |
| Publisher: | BBC Open University |
| Keyword(s): | Filter response; Filters; Impedance; Phasor diagram; Phasor representation; Spectrum analyser; Telephone; Television; Transfer characteristics |
| Footage description: | Gaby Smol introduces the programme. He uses a simple R-C filter and circuit diagram to explain and demonstrate the principles of filters. Input and output sinusoidals are compared for different frequencies. David Crecraft explains what a phasor is. He uses a phasor diagram to make his points, then goes on to explain how a phasor is related to complex numbers. Crecraft, with the aid of an animated sequence, shows how the complex expression for frequency response can be calculated from the components of the low pass R-C filter. Smol joins in. He demonstrates a machine which represents phasors graphically. Crecraft displays his speech waveform on an oscilloscope and then displays its spectrum on a spectrum analyser. He explains how the spectrum analyser works. Crecraft uses the spectrum analyser to measure the frequency response of a telephone filter. A sample of Crecraft's speech is analysed with the amplitude frequency response displayed. Crecraft examines the pulse response (step response) of a telephone filter. Smol shows a television test card and points out its features. He goes on to discuss the spectrum of a T.V. signal and then passes a signal through a filter. Smol explains the reasons for the result. Smol sums up. Credits. |
| Master spool number: | 6HT/71887 |
| Production number: | 00525_5220 |
| Videofinder number: | 1342 |
| Available to public: | no |
