Study of excitation signals parameters for portable bioimedical devices

The aim of this paper is to select the suitable excitation signal for a portable biomedical system based on the simulations of different signals while respecting the constraints on the system including excitation time, energy consumption, cost and ease of generation and at the same time guarantying the safety of the patient by limiting the current´s magnitude. In order to get the optimum working point that minimize the trade-off between the quality of the reconstructed signal, the time consumption and the hardware complexity when applying the perturbation signal to the system under test, the interaction between pertinent parameters is determined. These parameters are the number of the samples, the sampling frequency and the noise´s level. The number of samples (N) is directly related to the memory´s size of the hardware used in the measurement, the sampling frequency (Fs) is associated to the clock and the noise´s level is affiliated to the algorithm or the measurement hardware. To achieve a good signal´s reconstruction, the ratio (Fs/f) should be lower than (~2*N) and the window´s size which is proportional to (N, Fs/f) as large as possible.