Software Defined Radio Subsampling Receiver for Wireless Monitoring and Sensing Medical Applications

In hospitals, telemetry is utilized by physicians to provide accurate diagnosis for their patients. The increase penetration of wireless technology in healthcare environment for powering, monitoring and sensing purposes of implanted or attached devices to human patients´ triggered new challenges in designing reconfigurable wireless transceiver intended for healthcare that can operate in multi-frequency mode. To minimize the number of RF receivers needed for these kind of applications, a broadband subsampling receiver is proposed. Recently, this technique has been proposed for software defined radio (SDR) applications to allow multiple and concurrent RF signal digitization directly from the RF stage by using a sampling frequency much lower than the RF frequency. In this paper, band-pass sub-sampling technique widely used in many applications, such as radar, sonar, data acquisition, measurement and instrumentation is reviewed. An efficient subsampling algorithm is proposed to determine the sampling frequency needed such that interferences between the different monitoring and sensing medical signals is mitigated. Measurement results are provided with RF instrumentation equipment and a low speed ADC to validate the proposed architecture for multi- frequency monitoring and sensing applications.