Devices and systems are provided to electrically and optically detect hemodynamic properties of a body. Such devices are configured to detect electrocardiographic signals and photoplethysmographic signals and to operate a single analog-to-digital converter (ADC) to sample one or more of each of such signals. This includes operating a multiplexer to connect electrical signals related to the detected optical and electrical properties to the single ADC during respective different sampling times or periods. This can include connecting the detected electrocardiographic signals and photoplethysmographic signals to the ADC during alternating periods of time. Using a single ADC to sample one or more of each of electrocardiographic signals and photoplethysmographic signals can provide samples of such signals that have a relative timing that is known, stable, and controllable.
