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The problem is how the phase φ effects the outcome when the input(message signal) is the DSB-SC LSB. It's :
message: \$m(t)=A_{m}cos(ω_{m}t)\$
carrier: \$c(t)=A_{c}cos(w_{c}t)\$

I found that the LSB through the DSB-SC
\$DSB(t)=A_{c}A_{m}cos(ω_{m}t)cos(w_{c}t)=(A_{c}A_{m}/2)[cos((ω_{m}-ω_{c})t)+cos((ω_{m}+ω_{c})t)]\$

The component \$(A_{c}A_{m}/2)[cos((ω_{m}-ω_{c})t)]\$ is the expression for the LSB(t)

So the LSB(t) gets mixed with a Local Oscillator
\$LO(t)=Acos(w_{c}t+φ)\$
and the output d(t) passes through an Ideal LP Filter and the y(t) signal comes out of LPF. So I've reached that:
y(t)=\$(AA_{c}A_{m}/4)[cos((ω_{m}t+φ)]\$

enter image description here

I have reached at a dead end trying to understand the effect of phase φ when: φ=(0,π/4,π/2,3π/4,π)

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  • \$\begingroup\$ Problems and formulae but no apparent question. \$\endgroup\$ – Andy aka Dec 30 '15 at 12:36
  • \$\begingroup\$ The question is how the phase φ effects the system for each value it takes(0,π/4,π/2,3π/4,π) \$\endgroup\$ – Nick Dec 30 '15 at 20:53

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