Active signal processing personal health signal receivers

• US 9,083,589 B2
• Filed: 03/06/2014
• Issued: 07/14/2015
• Est. Priority Date: 11/20/2006
• Status: Active Grant

• Current Assignee: Proteus Digital Health, Inc. (Otsuka Holdings Company Limited)
• Original Assignee: Proteus Digital Health, Inc. (Otsuka Holdings Company Limited)
• Inventors: Arne, Lawrence, Au-Yeung, Kit Yee, Crandall, Kenneth C., Robertson, Timothy
• Primary Examiner(s): LEE, SIU M
• Application Number:
  US14/199,804
• Publication Number:
  US 20140334575A1
• Time in Patent Office: 495 Days
• Field of Search: 375/316, 375/345, 375/340, 375/342
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 5/0028 Body tissue as transmission medium, i.e. transmission systems where the medium is the human body
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 13/005 Transmission systems in which the medium consists of the human body
• CPC Class Codes: H04L 1/0036 arrangements specific to the receiver
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 27/152 using controlled oscillators, e.g. PLL arrangements
• CPC Class Codes: H04L 27/22 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/2271 wherein the carrier recovery circuit uses only the demodulated signals
• CPC Class Codes: H04L 27/2273 associated with quadrature demodulation, e.g. Costas loop

Abstract

The invention provides a receiver associated with a body, e.g., located inside or within close proximity to a body, configured to receive and decode a signal from an in vivo transmitter which located inside the body. Signal receivers of the invention provide for accurate signal decoding of a low-level signal, even in the presence of significant noise, using a small-scale chip, e.g., where the chip consumes very low power. Also provided are systems that include the receivers, as well as methods of using the same.

Claims

1. A signal receiver comprising:

an automatic gain controller configured to receive an encoded signal from an in vivo transmitter in a low signal to noise ratio (SNR) environment and to actively adjust the signal receiver to variations in frequency and power of the received encoded signal, and wherein the automatic gain controller is configured to determine a first frequency having a highest amplitude in a power spectrum of the received encoded signal;

a demodulator coupled to the automatic gain controller and configured to receive an output signal from the automatic gain controller, wherein the output signal comprises information regarding the first frequency, and reconstruct the encoded signal locked in frequency and phase to the received encoded signal and configured to approximate an original un-encoded signal, wherein the demodulator is tuned to the first frequency such that the demodulator is configured to adapt to changes in frequency of the received encoded signal;

a symbol recovery component configured to receive the reconstructed encoded signal and determine a signal clock of the reconstructed encoded signal and identify a start sequence in the reconstructed encoded signal, and wherein the symbol recovery component is configured to determine a phase of the reconstructed encoded signal, and produce a decoded signal with substantially no error.

2. The signal receiver according to claim 1, wherein the signal receiver has a high coding gain.

3. The signal receiver according to claim 2, wherein the signal receiver has a coding gain ranging from 6 dB to 12 dB.

4. The signal receiver according to claim 3, wherein the signal receiver has a coding gain ranging from 8 dB to 10 dB.

5. The signal receiver according to claim 4, wherein the signal receiver has a coding gain of 9 dB.

6. The signal receiver according to claim 1, wherein the SNR is 7.7 dB or less.

7. The signal receiver according to claim 1, wherein the signal receiver is configured to decode the encoded signal with 10% error or less.

8. The signal receiver according to claim 1, wherein the encoded signal is transmitted conductively.

9. The signal receiver according to claim 1, wherein the encoded signal is a signal that has been modulated using frequency shift keying (FSK), on off keying (OOK), amplitude modulation (AM), quadrature amplitude modulation (QAM), or binary phase shift keying (BPSK).

10. The signal receiver according to claim 9, wherein the encoded signal is a signal that has been modulated using binary phase shift keying (BPSK).

11. The signal receiver according to claim 1, further comprising a coherent demodulator functional block.

12. The signal receiver according to claim 11, further comprising a Costas loop demodulating functional block.

13. The signal receiver according to claim 1, further comprising an actively adjustable rate sampler, wherein the actively adjustable rate sampler in configured to adjust a sampling rate of the receiver based on the received encoded signal.

14. The signal receiver according claim 1, further comprising a decoder block configured to translate measured signals into data having a low probability of error.

15. The signal receiver according to claim 14, wherein the decoder block is configured to:

(a) convert the measured signals to hard code decision values;

(b) perform an error check on the hard code decision values to assess a likelihood of errors associated with the hard code decision values; and

(c) based on results of the error check, adjust the measured signals toward or away from a measurement point.

16. The signal receiver according to claim 1, wherein the signal receiver is sized to be stably associated with a living subject in a manner that does not substantially impact movement of the living subject, wherein the living subject is a human subject.

17. The signal receiver according to claim 1, wherein the signal receiver has a volume that is about 5 cm³ or less.

18. The signal receiver according to claim 3, wherein the signal receiver has a chip size limit ranging from 10 mm² to 2 cm².

19. The signal receiver according to claim 4, wherein the signal receiver has a volume that is about 1 cm³ or less.

20. The signal receiver according to claim 16, wherein the signal receiver is configured to be contacted with an external location of the human subject.

21. The signal receiver according to claim 1, wherein the signal receiver has a topical patch configuration.

22. The signal receiver according to claim 1, wherein the signal receiver is an implantable signal receiver that is configured to be implanted inside of a living subject.

23. The signal receiver according to claim 1, wherein the signal receiver is configured to retransmit data of the received encoded signal to a location external to a living subject.

24. The signal receiver according to claim 1, further comprising a power generation element.

25. The signal receiver according to claim 1, further comprising a data storage element.

30. A system comprising:

(a) a signal receiver according to claim 1; and

(b) an in vivo signal transmitter.

26. A method of transmitting data from an in vivo transmitter to a body associated receiver sized to be stably associated with a living subject in a manner that does not substantially impact movement of the living subject, the method comprising:

transmitting a modulated encoded data signal from the in vivo transmitter to the body associated receiver; and

receiving the modulated encoded data signal at the body associated receiver in accordance with the following method;

receiving the modulated encoded data signal in a low signal to noise ratio (SNR) environment and to actively adjust to variations in the frequency and power of the received modulated encoded data signal;

determining a first frequency having a highest amplitude in a power spectrum of the received modulated encoded data signal;

demodulating the received modulated encoded data signal and reconstructing the modulated encoded data signal locked in frequency and phase to the received modulated encoded data signal, wherein demodulating the received modulated encoded data signal and reconstructing the modulated encoded data signal comprises;

approximating, by a demodulator, an original un-encoded data signal, wherein the demodulator is tuned to the first frequency such that the demodulator is configured to adapt to changes in frequency of the received encoded signal; and

receiving the reconstructed modulated encoded data signal; and

determining a signal clock of the reconstructed modulated encoded data signal; and

identifying a start sequence in the reconstructed modulated encoded data signal; and

determining a phase of the reconstructed modulated encoded data signal; and

producing a decoded signal with substantially no error.

27. The method according to claim 26, further comprising actively adjusting a sampling rate of the modulated encoded data signal using an adjustable rate sampler.

28. The method according to claim 26, further comprising translating, by a decoder block, measured signals into data having a low probability of error.

29. The method according to claim 28, further comprising, by the decoder block of the signal receiver:

(a) converting the measured signals to hard code decision values;

(b) performing an error check on the hard code decision values and assessing a likelihood of errors associated with the hard code decision values; and

(c) based on results of the error check, adjusting the measured signals toward or away from a measurement point.

31. A signal receiver comprising:

an automatic gain controller configured to;

receive an encoded signal from an in vivo transmitter and to actively adjust the signal receiver to variations in frequency and power of the received encoded signal; and

determine a first frequency having a highest amplitude in a power spectrum of the received encoded signal;

a demodulator coupled to the automatic gain controller, the demodulator configured to;

receive an output signal from the automatic gain controller, wherein the output signal comprises information regarding the first frequency;

reconstruct the encoded signal locked in frequency and phase to the received encoded signal;

approximate an original un-encoded signal, wherein the demodulator is tuned to the first frequency to adapt to variations in frequency of the received encoded signal; and

a symbol recovery component configured to;

receive the reconstructed encoded signal;

determine a signal clock of the reconstructed encoded signal to identify a start sequence in the reconstructed encoded signal;

determine a phase of the reconstructed encoded signal; and

produce a decoded signal.

32. The signal receiver of claim 31, wherein the automatic gain controller comprises a buffer, and wherein the buffer is configured to store a plurality of samples of the encoded signal and send the plurality of samples to a Fast Fourier Transform component.

33. The signal receiver of claim 31, wherein demodulator is configured to output, to the automatic gain controller, a detected power of the output signal from the automatic gain controller and wherein the automatic gain controller is configured to actively adjust the signal receiver based on the detected power.

34. The signal receiver of claim 31, wherein the demodulator comprises a Costas loop demodulating functional block.

35. The signal receiver of claim 34, wherein the Costas loop demodulating functional block comprises a voltage-controlled oscillator, wherein the voltage-controlled oscillator is tuned according to the first frequency.

36. The signal receiver of claim 31, wherein the symbol recovery component is configured to implement a predetermined delay that is used to determine the signal clock of the reconstructed encoded signal.

37. The signal receiver of claim 31, wherein the symbol recovery component is configured to perform an early-late gate calculation to identify the start sequence in the reconstructed encoded signal.