Method for wireless communication transfer with an implanted medical device

• US 6,453,200 B1
• Filed: 04/26/1999
• Issued: 09/17/2002
• Est. Priority Date: 11/01/1996
• Status: Expired due to Fees

• Current Assignee: Nanotron Gesellschaft Fur Mikrotechnik mbH
• Original Assignee: Nanotron Gesellschaft Fur Mikrotechnik mbH
• Inventors: Koslar, Manfred
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US09/297,156
• Time in Patent Office: 1,240 Days
• Field of Search: 600/508-518, 607/60-61, 128/903
• US Class Current: 607/60
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique
• CPC Class Codes: H04B 7/00 Radio transmission systems, i.e. using radiation field H04B10/00, H04B15/00 take precedence

Abstract

Disclosed herein is a method and apparatus for wireless communication with a medical device implanted in the human body. In the method disclosed herein an information input signal undergoes an angle modulation in a transmitter and reaches a receiver through a transmission channel. Angle modulated information carrying pulses with a frequency spectrum are generated. The pulses are time compressed in the receiver using a filter with frequency dependent transit time. The pulses are created with shortened duration and increased amplitude compared to emitted pulses. The pulses on the transmitter side are imprinted with at least part of information constituting a message using a further modulation or encoding procedure of telecommunications. At least part of the information constituting the message is additionally imprinted onto the angle modulation.

Claims

1. A method for wireless communication with a medical device implanted in the human body, wherein in a transmitter an information input signal undergoes an angle modulation and reaches a receiver through a transmission channel, and further wherein angle modulated pulses carrying information possessing a frequency spectrum are generated in the transmitter and may be time compressed in the receiver using a frequency dependent delay time dispersion filter, and further wherein the pulses are created of shorter duration and increased amplitude compared to emitted pulses, wherein the pulses on a transmitter side undergo modulation or an encoding process and are imprinted with at least a part of information that constitutes a message, and wherein at least a part of the information that constitutes the message is also imprinted onto the angle modulation, wherein a quasi-Dirac pulse sequence is approximated in the transmitter and fed to a low-pass filter, the low pass filter characteristic of which possess a peak shortly before the critical frequency, and thus transforms the pulse sequence into a series of Sinc-pulses, having a shape of a Sinc function, which subsequently is carried to an amplitude modulator, which imprints a Sinc-shaped envelope onto each pulse of a carrier oscillation, and a signal generated after transformation is fed to a dispersive filter, at an output of which arrives a frequency modulated pulse sequence.

2. The method of claim 1, wherein the pulses are filtered according to a default filter response, and wherein the angle modulation on the transmitter side and the frequency dependent differential delay time response of the dispersion filter on a receiver side are matched, wherein spectral signal components of angle modulated pulses of an output signal arrive at an output of the dispersion filter essentially coincident, and with a corresponding increase in amplitude, due to a frequency dependent variable signal delay time of the dispersion filter.

3. The method of claim 2, wherein the angle modulated pulses are fed to at least two dispersion filters in the receiver, and further wherein variable delay time responses of the dispersion filters and modulation characteristics that are used on the transmitter side are matched in pairs, wherein spectral signal components of frequency modulated pulses arrive essentially coincident, with a corresponding increase in amplitude, at an output of only one of the at least two dispersion filters, while this compression does not take place for the corresponding other of the at least two dispersion filters.

4. The method of claim 1, wherein the pulses undergo additional modulation, the additional modulation selected from the group consisting of pulse position modulation, pulse code modulation, differential pulse code modulation, pulse delta modulation, and combinations thereof.

5. The method of claim 4, wherein the angle modulation and the additional modulation form independent, orthogonal, or approximately orthogonal modulation types.

6. The method of claim 1, wherein each pulse of a carrier frequency of an input signal is subjected to the angle modulation in the transmitter.

7. The method of claim 1, wherein an amplitude of pulses compressed by the dispersion filter is interpreted using a detector.

8. The method of claim 1, the angle modulation occurs according to a default modulation characteristic, that determines a time variation of a phase angle during a duration of a pulse, according to a predetermined time-variant behavior, an amplitude of an angle modulated pulse for imprinting information contained in an input signal is preset depending on the input signal, in the receiver the angle modulated pulses are fed to a dispersion filter, a delay time response of which is matched to the modulation characteristic of the angle modulation by a reverse time-variant behavior wherein spectral signal components of the angle modulated pulses arrive essentially coincident, and with a corresponding increase in amplitude, at an output of the dispersion filter, an amplitude of the pulses, compressed by the dispersion filter, is evaluated, for recovery of information contained in the input signal, using a detector, the detector being an amplitude demodulator.

9. The method of claim 8, wherein during pulse duration of pulse modulated signals, an angle, a frequency or a phase of a carrier frequency changes over time during the pulse duration, linearly or nonlinearly according to a predetermined profile, monotonically from a lower frequency or phase position to an upper frequency or phase position, or monotonically from an upper frequency of phase position to a lower frequency or phase position, wherein dispersion filters in the receiver possess a corresponding complementary response.

10. The method of claim 9, wherein the predetermined profile changes within a pulse sequence in relation of individual pulses to each other, and wherein the profile change is also part of information contained in the input signal.

11. The method of claim 1, wherein to facilitate communication between the transmitter and receiver, a predetermined digital reference signal is transmitted as an input signal to align the transmitter and the receiver, during communication facilitation an amplitude or a pulse duration of an output signal of the dispersion filter on a receiver side is measured, and a modulation characteristic used on a transmitter side, or a frequency dependent delay time response of the dispersion filter on the receiver side, is modified, until the pulse duration at an output of the dispersion filters in the receiver reaches a minimum value, or an amplitude reaches a maximum value.

12. The method of claim 1, wherein the signal flow in the receiver is split into two parallel branches, each with two dispersion filters with frequency dependent delay time characteristics, that are inverse with respect to each other, the signal flow in the two branches is connected through or interrupted for a predetermined time interval during each pulse, whereby the interruption or connection occurs synchronous to the transmission timing rate, the two branches are joined on the output side by a subtracter.

13. The method of claim 1, wherein the frequency of the carrier signal is in the range between 400 MHz and 1 GHz.