MSP430 implementation of wavelet transform for purposes of physiological signals processing

The Wavelet Transform in its discrete form has been applied to a wide range of biomedical signals so far. Typically, its calculation is performed off-line and calculation systems suffer from limited autonomy, bulkiness and obtrusiveness. Recently, an increased interest has been paid to telemedicine and medical embedded systems where miniature, low-cost, autonomous and ultra-low-power devices play a major role. Such devices are usually based on microcontrollers, which in addition to other tasks need to perform signal processing, very often in real-time. This paper presents a methodology to perform Wavelet Transform on microcontrollers from Texas Instruments MSP430 series. By using presented optimizations the Electrocardiogram and Photoplethysmographic signals are processed in real time for purposes of QRS complex extraction and denoising. After the theoretical considerations on wavelets and their optimization in integer arithmetic, the computation architectures are presented. The following are the presentation of obtained results and some guidelines for future work. The same approach can be applied with other signals and microcontrollers, where the embedded implementation of wavelets can be beneficial.