1 research outputs found
Investigation of high bandwith biodevices for transcutaneous wireless telemetry
PhD ThesisBIODEVICE implants for telemetry are increasingly applied today in various areas
applications. There are many examples such as; telemedicine, biotelemetry, health care,
treatments for chronic diseases, epilepsy and blindness, all of which are using a wireless
infrastructure environment. They use microelectronics technology for diagnostics or monitoring
signals such as Electroencephalography or Electromyography. Conceptually the biodevices are
defined as one of these technologies combined with transcutaneous wireless implant telemetry
(TWIT). A wireless inductive coupling link is a common way for transferring the RF power and
data, to communicate between a reader and a battery-less implant. Demand for higher data rate
for the acquisition data returned from the body is increasing, and requires an efficient modulator
to achieve high transfer rate and low power consumption. In such applications, Quadrature Phase
Shift Keying (QPSK) modulation has advantages over other schemes, and double the symbol rate
with respect to Binary Phase Shift Keying (BPSK) over the same spectrum band. In contrast to
analogue modulators for generating QPSK signals, where the circuit complexity and power
dissipation are unsuitable for medical purposes, a digital approach has advantages. Eventually a
simple design can be achieved by mixing the hardware and software to minimize size and power
consumption for implantable telemetry applications. This work proposes a new approach to
digital modulator techniques, applied to transcutaneous implantable telemetry applications;
inherently increasing the data rate and simplifying the hardware design. A novel design for a
QPSK VHDL modulator to convey a high data rate is demonstrated. Essentially, CPLD/FPGA
technology is used to generate hardware from VHDL code, and implement the device which
performs the modulation. This improves the data transmission rate between the reader and
biodevice. This type of modulator provides digital synthesis and the flexibility to reconfigure and
upgrade with the two most often languages used being VHDL and Verilog (IEEE Standard)
being used as hardware structure description languages. The second objective of this thesis is to
improve the wireless coupling power (WCP). An efficient power amplifier was developed and a
new algorithm developed for auto-power control design at the reader unit, which monitors the
implant device and keeps the device working within the safety regulation power limits (SAR). The proposed system design has also been modeled and simulated with MATLAB/Simulink to
validate the modulator and examine the performance of the proposed modulator in relation to its
specifications.Higher Education Ministry in Liby