Question 6
- State two differences between a 625 line monochrome and colour television receivers.
- In a 625 line colour television receiver, state the frequency of the following units: (i) horizontal oscillator; (ii)vertical oscillator; (iii)sub-carrier; (iv) sound frequency.
Observation
The expected answers were:
(a) (i) Monochrome Television Receiver has one electron gun whilst the colour television has three electron guns.
(ii) Monochrome Television Receiver has a single raster whilst colour television has three rasters.
(iii) Monochrome Television Receiver has a single video signal whilst a colour television receiver has two video signals (luminance and chrominance signals)
(b) (i) Horizontal Oscillator - 15625 Hz.
(ii) Vertical Oscillator - 50 Hz
(iii) Sub carrier - 4.43 MHz
(iv) Sound frequency - 5.5/6 MHz
The question was on Communication Systems. The question was popular with the candidates. The performance was fairly good.