Communication Systems - Engineering

Q1:

In Modulation, "carrier" is

A resultant wave

B speech voltage to be transmitted

C voltage with constant frequency, phase or amplitude

D voltage for which frequency, phase or amplitude is varied

ANS:D - voltage for which frequency, phase or amplitude is varied

In Modulation process carrier signal only carries the modulating or base band signal x(t) , because the carrier signal is a high frequency signal and x(t) is low frequency signal.

So to transmit the low frequency signal we need a carrier. The amplitude, frequency and phase also vary.