Date of Award

Spring 1995

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)


Biomedical Engineering

First Advisor

Jeutter, Dean

Second Advisor

Prieto, Thomas

Third Advisor

Ropella, Kristina


A miniature single-channel heart rate monitoring device has been developed specifically for use in critical care situations. The externally-worn device is placed directly on the chest above the heart, allowing acquisition of the electrocardiogram without the use of leads. The 8-bit microcontroller-based transmitter digitizes the preconditioned ECG and identifies the signal in real-time using a robust QRS detection algorithm. A dual tone multifrequency tone (DTMF) is generated by the microcontroller after a valid QRS complex is detected. A DTMF tone consists of two low frequency sine waves which are added together. Different tones are generated indicating either normal sinus rhythm, bradycardia, tachycardia, or low battery condition. The DTMF tone burst is transmitted by frequency modulation to a nearby nurses' station. At the monitoring station, the transmitted data is demodulated and decoded by the receiver system which then activates the appropriate LED's, and possibly the alarm. In addition, the system's design features minimal power consumption and size, accurate transmission and recovery of data, low cost, repeated use, and reliable heart rate detection.



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