Wireless communications and embedded sensing, processing and actuation systems have had an outstanding development allowing to emergence innovative applications in several fields such as entertainment, medical, industrial or environmental to mention a few. Up to the point that currently the presence of such sensing systems is widespread in everyday life improving the quality of life, safety and health of human beings. However, one of the main constraints encountered in low-voltage power-efficient sensors is the low output signal level to be detected that can be largely exceeded by noise levels in the environment, what demand special amplification techniques to extract the information. One possibility is the use of lock-in amplifiers (LIAs), based on a technical known as phase-sensitive detection which allows measuring the amplitude and phase of very small signals even if there noise sources several orders of magnitude greater than the signal itself.