A Wireless Medical Surveillance System

Studienarbeit von Michael Krause

Abstract:

This thesis has the development of a Digital Signal Processor (DSP) based on an Electro-Cardiogram (ECG) analysis system as its main theme. The system measures cardiac signals using two surface ECG leads from which individual heartbeats and pulse trends are extracted. Processed information can be presented on any Bluetooth enabled Personal Digital Assistant (PDA).

The system combines several technologies, e.g. signal measuring and forming unit, DSP hard- and software and a WAP1 server with Bluetooth interface. A basis for this project was a master's thesis that investigates and implements WAP over Bluetooth (see Chapters 5 and 6).

The focus of this work is hardware and software design of the ECG measurement and DSP system. The DSP software includes implementation of medical real-time algorithms for heart beat detection, average beat and pulse trend calculation. All algorithms have been implemented using the C language.

Inhaltsverzeichnis:

	Abstract	2
	Acknowledgement	3
	Contents	4
	Figures	6
1.	Introduction	8
1.1	System overview	8
1.2	Functional description	9
2.	Introduction into heart anatomy, cardiac signals and measuring methods	10
2.1	The heart and the atrial contraction	10
2.2	Cardiac signal characterization and measuring methods	12
3.	Hardware	14
3.1	Hardware architecture	14
3.2	Analog measurement hardware design	14
3.2.1	System architecture	15
3.2.2	Patient safety aspects	16
3.2.3	Detailed system description	17
3.3	DSP hardware	26
3.3.1	Development board overview	26
3.3.2	TI TMS320C5402 DSP features	27
3.3.3	DSP and DSP board integration	29
4.	Software	31
4.1	DSP software architecture	31
4.2	Main program	32
4.3	Sensor data acquisition and voltage supervision	33
4.3.1	McBSP	33
4.3.2	DMA controller	36
4.3.3	Timer operation	39
4.4	Digital signal processing	40
4.4.1	Signal preprocessing	41
4.4.2	Beat detection and pulse calculation	49
4.4.3	Average beat and pulse trend calculation	50
4.4.4	Preamplifier gain setting	51
4.5	WAP server communication	51
4.5.1	UART	51
4.5.2	EWS commands and UART ISR	52
4.6	Labview PC-application	53
5.	Embedded WAP-server	55
5.1	Wireless Application Protocol	55
5.1.1	The WAP concept	55
5.1.2	WAP servers	57
5.2	Embedded WAP server (EWS)	57
5.3	Medical surveillance WAP application	58
6.	Bluetooth interface	60
6.1	Introduction into Bluetooth	60
6.2	WAP over Bluetooth (WOB) Implementation	62
7.	Conclusions	63
8.	References	64
	Appendix A - ECG measurements hardware	65
	Appendix B - DSP software source code	73
	Appendix C - Labview PC application source code	90