Correct Answer - Option 4 : 1

1) General equation of SSB modulated wave:

\(s\left( t \right) = \frac{{{A_C}{A_m}}}{2}cos\;2\pi \left( {{f_c} + {f_m}} \right)t\)

2) Output of envelope detector to signal

Acos ω_{c}t → A

__Application:__

Equation of SSB modulated signal

A_{c} = A_{m} = 1

\(s\left( t \right) = \frac{1}{2}\cos \left( {{\omega _c} \pm {\omega _n}} \right)t\)

the output of envelope detector = ½

The output of the envelope detector is a constant voltage signal

Hence option (d) which represents a constant voltage is correct.