Question
Due to economic reasons, only the upper sideband of an AM wave is transmitted, but at the receiving station, there is a facility for generating the carrier. Show that if a device is available which can multiply two signals, then it is possible to recover the modulating signal at the receiver station.
Solution
The received signal is given by,
A1 cos (ωc + ωm) t
Carrier signal is given by,
Ac cos ωc t
where,
The carrier Ac cos ωct is available at the receiving station.
On multiplying the two signals, we get
If this signal is passed through a low-pass filter, it will pass through the high frequency signals and block the low frequency signals.
Thus, modulating signal, is given by
of a single frequency .
