The ´Phase-Reversal´ in DSB-SC: A Comment

There has been an accepted fact that the double-side-band-suppresssed-carrier (DSB-SC) waveform is always accompanied by a ´phase-reversal´, whenever the message goes through zero. In this work, we demonstrate that for ´phase-reversal´ to exist in the DSB-SC modulated waveform, the zero-crossing of the message has to be accompanied by the zero-crossing of the carrier. This observation though small is significant, because, in a laboratory implementation of the DSB-SC modulator, generated using two independent signal generators for the carrier and the message, a student desperatly tries to observe the ´phase reversal´ which has an extremely low probability of occuring (equal to that of having two independent signal sources in phrase coherence). In this work, we prove this observation through simulation and experimental results.