Assignment:
Multiplication of a carrier by a modulating signal generates an AM waveform known as DSB-SC, the waveform is
v(t) DSB-SC = Ac cos W ct x Vm cos Wmt
Where W = is the angular velocity
a. Make a sketch of the DSB-SC waveform with Vm = 1 V and Ac = 10 V for a carrier frequency of 10 kHz and a modulating signal frequency of 1 kHz. Show one cycle of the modulating signal frequency. Make sure you label your axes correctly!
b. Draw a single sided spectral diagram for the DSB-SC waveform in part (a) above.
c. DSB-SC signals cannot be demodulated with an envelope detector. Describe one way in which a DSB-SC signal can be demodulated.
d. Why is DSB-SC modulation used to transmit stereo information in FM broadcast signals rather than DSB-LC AM?
e. Stereo information is transmitted in the baseband of FM broadcasts using DSB-SC modulation of a 38 kHz sub-carrier. A diagram of the demodulator that recovers L+R and L-R audio channels is show in slide 33 of the power point file of Module 10. How is the 38 kHz locally generated signal that is used to drive the DSB-SC multiplier derived from the baseband signal at the output of the FM demodulator?
Provide complete and step by step solution for the question and show calculations and use formulas.
