NCERT Physics Class 12 Exemplar Ch 15 Communication Systems Part 6 (For CBSE, ICSE, IAS, NET, NRA 2022)

Glide to success with Doorsteptutor material for CBSE/Class-12 : get questions, notes, tests, video lectures and more- for all subjects of CBSE/Class-12.

Frequencies present are



1. Plot of amplitude versus is shown in the Figure.

Plot of Amplitude Versus Ωis
  • As can be seen frequency spectrum is not symmetrical about . Crowding of spectrum is present for .
  • Adding more modulating signals lead to more crowding in w < w c and more chances of mixing of signals.
  • Increase band-width and to accommodate more signals. This shows that large carrier frequency enables to carry more information (more ) and which will in turn increase bandwidth.

Q 30 An audio signal is modulated by a carrier wave of 20MHz such that the bandwidth required for modulation is 3 kHz. Could this wave be demodulated by a diode detector which has the values of R and C as

(i) .

(ii) .

(iii) .


So , is satisfied

(ii) .

Here too

So this too can be demodulated


Here so this cannot be demodulated

Developed by: