A Signal Based Clocking Scheme for A/D Converters in Body Sensor Networks

The importance of body sensor networks to monitor patients over a prolonged period of time has increased with an advance in home healthcare applications. Sensor nodes need to operate with very low-power consumption and under the constraint of limited memory capacity. Therefore, it appears wasteful to digitize the sensor signal at a constant sample rate, given that the frequency contents of body signals vary with time. In this paper a low-power analog system is proposed, which adjusts the converter clock rate to suit the momentary requirement of the signal to be converted. Simulation of the system at the circuit level shows a significant reduction in the average sample frequency and data rate of 50% and 35% respectively compared to the conventional approach