Example of Application

Monitoring Human Heartbeat and Respiration

SDR-KIT 580B, 980B, and 2500B can be used for non-contacting monitoring specific biometric modulations, such as heart beat, respiration, arm and leg movements or other biometric patterns induced by human body’s micro movements.  One application is to monitor human sleep pattern for diagnosis of obstructive sleep apnea syndrome (OSAS) or detection of sudden infant death syndrome (SIDS) during sleep.  OSA is a common, widely underdiagnosed condition associated with significant morbidity and mortality. Due to intermittent anatomical blockage of the upper airway, reduction or even cessation of airflow occurs during sleeping, resulting in recurrent oxygen desaturation and sleep fragmentation.

Due to the weakness of biometric modulated signals by heart beats and breathing, any environmental clutter, multipath propagation, undesired direct coupling effect from transmitted energy, system flicker noise, and other causes can overwhelm the biometric signals. Thus, after data recording, effective digital signal processing algorithms for extracting informative biometric signals and estimating physiological parameters must be used.  The respiration and heartbeat signals are extracted separately. The system architecture is illustrated below:

human respiration 1

We tested the extraction of human respiration pattern and heartbeat pattern using SDR-KIT 980B centered at 9.8 GHz with 400 MHz bandwidth as below:

The respiration pattern and heartbeat pattern are extracted from the respiration processor and the heartbeat processor separately. The extracted respiration pattern shows the respiration period of 2-3 sec and the heartbeat period of around 1 sec.