Detection of SSB signals

A single sideband signal is just an AM signal, minus carrier and one of the sidebands.  If BFO frequency of a CW receiver is set where the carrier should be, the sideband, may be upper or lower, will beat against BFO and produce audio output. In this manner, the receiver of the figure given can be used to detect SSB.

The BFO frequency is critical for a better SSB reception.  If it is not set exactly at frequency of suppressed carrier, the voice will sound bizarre, like monkey chatter. A advanced method of receiving CW, FSK, and SSB uses a product detector.  This is a specialized form of mixer.