Available online
Description
Second of two programmes on power amplifier design deals mainly with distortion and harmonic or frequency analysis of waveforms
Second of two programmes on power amplifier design deals mainly with distortion and harmonic or frequency analysis of waveforms
| Module code and title: | TS282, Electromagnetics and electronics |
|---|---|
| Item code: | TS282; 13 |
| First transmission date: | 15-07-1972 |
| Published: | 1972 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:20:24 |
| + Show more... | |
| Producer: | Tony Jolly |
| Contributors: | David Crecraft; John Sparkes |
| Publisher: | BBC Open University |
| Keyword(s): | 500 Hz sine wave; Amplifiers; Frequency analyser; Large screen oscilloscope; Sine waves; Square wave; Waveforms |
| Footage description: | David Crecraft considers the output stage described in Unit 13. A 500Hz, sinewave is applied to the input and the output monitored on a large screen oscilloscope and by a small loudspeaker. Effects of severe cross over distortion and of overload clipping are demonstrated by short-circuiting the diodes and increasing the input amplitude, respectively. John Sparkes uses a waveform synthesiser and a frequency analyser to demonstrate Fourier analysis, even and odd harmonic distortion, and the effect of overloading the input of a long-tailed pair differential amplifier. Sparkes then uses the frequency analyser to show the harmonic content of the output signal under severe crossover and also overload conditions. Finally Sparkes and Crecraft demonstrate the effect of amplification and crossover distortion on speech. Sparkes' voice is fed via microphone and pre amplifier to the output stage, and sound obtained directly from its speaker. With the diodes shortcircuited the speech becomes almost unintelligible. |
| Master spool number: | 6LT/70612 |
| Production number: | 00525_5003 |
| Videofinder number: | 707 |
| Available to public: | no |
