Spread spectrum telemetry of physiological signals

• US 5,381,798 A
• Filed: 11/02/1993
• Issued: 01/17/1995
• Est. Priority Date: 11/02/1993
• Status: Expired due to Term

• Current Assignee: Cardiac Science Operating Company (Cardica Incorporated)
• Original Assignee: Quinton Instrument Co. (Cardica Incorporated)
• Inventors: Burrows, Fremont W.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US08/146,260
• Time in Patent Office: 441 Days
• Field of Search: 728/630, 728/696, 728/903, 607/32, 607/60
• US Class Current: 600/509
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: Y10S 128/903 Radio telemetry
• CPC Class Codes: Y10S 128/904 Telephone telemetry

Abstract

A system for the transmission of physiological signals from a patient to a display analysis and/or recording device using a spread spectrum transmission technique to reduce interference with the detection of the transmitted physiological signal wherein multiple channels of the physiological signals are transmitted over a bandwidth of approximately 3 MHz.

Claims

1. A system for the transmission of physiological signals from a patient to a data receiving device comprising;

a physiological data acquisition system for the detection of the desired physiological data from the patient and for processing an analog signal corresponding thereto;

an analog to digital conversion device operatively associated with said acquisition system for converting said analog signals corresponding to said physiological data to a serial digital data stream;

a spread spectrum signal transmission device which combines said serial digital data stream with a digital code sequence to form a combined transmission signal which is transmitted over a wide frequency bandwidth;

a spread spectrum signal receiving device which receives said combined transmission signal;

a data signal demodulation device for separating said serial digital data stream from said digital code sequence;

a data reformatting processor for the receipt and processing of said serial digital data stream from said demodulation device; and

a physiological data display, recording and/or analysis device for the receipt of the output from said reformatting processor.

2. The system of claim 1 wherein said reformatting processor converts said serial digital data stream to an analog data signal for use by said data display, recording and/or analysis device.

3. The system of claim 1 wherein said reformatting processor is operatively associated with a synchronization detection circuit.

4. The system of claim 3 wherein said synchronization detection circuit detects frame synchronization and provides a word framing pulse for use by the reformatting processor.

5. The system of claim 1 wherein said combined transmission signal is transmitted as a direct sequence modulated spread spectrum signal.

6. The system of claim 1 wherein said combined transmission signal is transmitted as a frequency hopping spread spectrum signal.

7. The system of claim 1 wherein said combined transmission signal is transmitted as a chirp modulated system.

8. The system of claim 1 wherein said physiological data acquisition system receives physiological data via sensors or electrodes operatively located on the patient and said data is amplified and digitized to provide said serial digital data stream for use by said spread spectrum signal transmission device.

9. The system of claim 1 wherein said spread spectrum signal transmission device provides a data clock signal for use by said physiological data acquisition system.

10. The system of claim 1 wherein said combined transmission signal is transmitted in a radio frequency range of about 902 to 928 MHz.

11. The system of claim 1 wherein said combined transmission signal has a bandwidth of about 3 MHz or more.

12. A method for transmitting physiological signals from a patient to a data receiving device comprising;

acquiring physiological signals from a patient;

processing an analog signal corresponding to the physiological signals of the patient;

converting the analog signal to a serial digital data stream;

combining the serial data stream with a digital code sequence to form a combined transmission signal;

transmitting the combined transmission signal between a spread spectrum transmitter and a spread spectrum receiver;

receiving the combined transmission signal and separating the serial digital data stream from the digital code sequence;

reformatting the serial digital data stream; and

receiving the reformatted serial digital data stream with a physiological data display, recording and/or analysis device.

13. The method of claim 12 wherein the analog signal is converted to a digital data stream by an A to D converter and the display, recording and/or analysis device receives the reformatted serial digital data stream from a data reformatting processor.

14. The method of claim 13 wherein the reformatted serial digital data stream is applied to a D to A converter which provides analog data to the display, recording and/or analysis device.

15. The method of claim 12 wherein the combined transmission signal is transmitted to the receiver via a direct sequence modulation system.

16. The method of claim 12 wherein the physiological signals are ECG waveforms from a patient, and the display, recording and/or analysis provide a visual display of the ECG waveform received from the patient.

17. The method of claim 12 wherein the analog signal is converted to a digital signal and then filtered and downsampled by a digital signal processor.

18. The method of claim 17 wherein the digital signal is also differentiated by the digital signal processor.

19. The method of claim 12 wherein the serial digital data stream is received by a synchronization detector circuit which provides a word synchronization pulse to a data reformatting processor.

20. The method of claim 12 wherein the serial digital data stream is reformatted by a data reformatting processor which receives the serial digital data stream and a clock signal from the spread spectrum receiver and a word synchronization pulse from a synchronization detector circuit.