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Question
I-V characteristics of four devices are shown in Figures.
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 |
 |
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| (i) | (ii) | (iii) | (iv) |
Identify devices that can be used for modulation.
Options
'i’ and ‘iii’.
only ‘iii’.
‘ii’ and some regions of ‘iv’.
All the devices can be used.
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Solution
‘ii’ and some regions of ‘iv’.
Explanation:
A square law modulator is a device which can produce modulated waves by the application of the message signal and the carrier wave.
A square law modulator is used for modulation purposes. Characteristics shown by (i) and (iii) correspond to linear devices.
And by (ii) corresponds to the square law device which shows non-linear relations. Some parts of (iv) also follow square law.
Hence, (ii) and (iv) can be used for modulation.
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