This paper proposes a methodology for Pulse Transmit Time measurement for purposes of cuff-less monitoring of Blood Pressure. The ECG and PPG signals are simultaneously acquired and Pulse Transmit Time is determined as a time between R peak in ECG and maximal slope in PPG. To distinguish characteristic points Discrete Wavelet Transform, Derivative Filtering, Modulus Maxima and additional functions are employed and translated in VHDL code and then embedded in a single chip from FPGA technology. The system works on-line, achieving accuracy of 97.53% and 97.09% for R peak and slope detection respectively. The emphasis is given to the description of signal processing approach, system architecture and working principles of fundamental components. Also, the preliminary testing results are presented.
- discrete wavelet transforms
- field programmable gate arrays
- approximation method