Question

Form an AM DSBFC envelope with a 40V positive maximum voltage and a 10V positive minimum voltage, determine (a) the unmodulated carrier amplitude, (b) the peak change in amplitude of the modulated wave, and (c) coefficient of modulation and percent modulation.

Answer 1

a)

$E_c=(V_{max}+V_{min})/2=(40+10)/2=25$ Vp

b)

$E_m=(V_{max}-V_{min})/2=(40-10)/2=15$ Vp

c)

coefficient of modulation:

$m=E_m/E_c=15/25=0.6$

percent modulation:

$M=100m=0.6\cdot100=60\%$