A system for measuring properties of a medium includes an electromagnetic generator for forming a CW carrier, a digital encoder for forming a digital message, and a modulator for modulating the CW carrier with the digital message to form a digitally modulated CW carrier. The medium provides a channel for propagating the digitally modulated CW carrier. The system further includes a receiver configured to receive the propagated, digitally modulated CW carrier, and a processor for measuring at least one property of the medium. The medium may be disposed within a gaseous atmosphere, a body of water, or a cell of a laboratory.