Explain amplitude modulation. Derive the voltage equation of an AM wav

1.	Explain amplitude modulation. Derive the voltage equation of an AM wave.
Answer» Let the instantaneous voltage of modulating signal be given by the expression V_m = V_m Sin ωt. Let the instantaneous voltage of high frequency carrier be given by v_c = V_csinω_ct. In amplitude modulation, amplitude of carrier varies proportional to instantaneous amplitude of modulating signal. Hence amplitude of modulated signal is A = V_c + V_m = V_c + V_m sin ω_mt = Vc[1 + \(\frac{V_m}{V_c}\)sin ω_mt] = Vc[1 + m_a Sin ω_mt ] The instantaneous value of amplitude modulated signal is V_Am = A Sin ω_ct V_am - Vc[1 + m_a Sinω_mt] Sin ω_ct. where m_a is called modulation index.

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