A device for measuring impedance of biological tissue may include a pair of electrodes for contacting the biological tissue, and a drive circuit coupled to the pair of electrodes and configured to drive an alternating current (AC) through the biological tissue and to sense an AC voltage. The AC voltage is towards a reference voltage on at least one of the pair of electrodes. The device may include at least one single-ended amplitude modulation (AM) demodulator configured to demodulate the AC voltage and to generate a corresponding baseband voltage representing the impedance, and an output circuit configured to generate output signals representative of DC and AC components of the baseband voltage.