## 4 Experimental Results
### Prototype Performance Evaluation  
To evaluate the performance of the developed prototype, a previously calibrated ABPMD [41] was considered and a comparison between the calibration results that were obtained with the proposed prototype and the calibration results obtained with a commercial and certified BP calibrator [41; 43] was performed. Regarding the ABPMD that was used to compare the experimental calibration results, it is important to note that this BP monitor is clinically validated in accordance with multiple certified entities, which includes the European Society of Hypertension (ESH) and the German Association for High Blood Pressure (DHL), among others. The commercial and certified BP calibrator that was used for the comparative performance evaluation is a modular calibrator. It is very versatile and supports the maintenance and calibration of NIBP equipment from the simplest commercial ABPMD for home usage to highly accurate equipment used in hospital intensive care units [44]. The previously referred to NIBP monitor has the following main specifications: NIBP measurement capability using the oscillometric algorithm; capability to measure the cardiac rate in the range between 20 and 240 beats per minute (BPM) with an accuracy equal to \(\pm\)0.25 BPM; minimum diastolic blood pressure measurement capability of 15 mmHg and maximum systolic pressure measurement capability of 275 mmHg. The \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**AMP**} & \multirow{2}{*}{**SBP**} & \multirow{2}{*}{**DBP**} & \multirow{2}{*}{**MAP**} & \multicolumn{3}{c}{**Absolute Error (mmHg)**} & \multicolumn{3}{c}{**Relative Error (\%)**} & \multicolumn{3}{c}{**HBR_M**} & \multicolumn{1}{c}{**HBR_M**} \\ \cline{5-13}  & & & & **SBP** & **DBP** & **MAP** & **SBP** & **DBP** & **MAP** & **(av)** & **(std)** & **N\_Peaks** \\ \hline
1 & 108.4 & 91.6 & 100.0 & \(-11.6\) & 11.6 & 0.0 & \(-9.7\) & 14.5 & 0.0 & NaN & 0.0 & 10 \\ \hline
2 & 123.1 & 83.6 & 99.8 & 3.1 & 3.6 & \(-0.2\) & 2.6 & 4.4 & \(-0.2\) & 87.9 & 1.0 & 28 \\ \hline
3 & 120.3 & 78.8 & 99.3 & 0.3 & \(-1.2\) & \(-0.7\) & 0.3 & \(-1.5\) & \(-0.7\) & 91.4 & 0.5 & 29 \\ \hline
4 & 121.4 & 81.0 & 99.3 & 1.4 & 1.0 & \(-0.7\) & 1.2 & 1.2 & \(-0.7\) & 88.1 & 0.2 & 29 \\ \hline
5 & 118.2 & 81.7 & 100.2 & \(-1.8\) & 1.7 & 0.2 & \(-1.5\) & 2.1 & 0.2 & 90.3 & 0.3 & 29 \\ \hline
6 & 120.7 & 81.7 & 99.9 & 0.7 & 1.7 & \(-0.1\) & 0.6 & 2.1 & \(-0.1\) & 89.2 & 0.2 & 28 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Absolute and relative errors of the evaluation of the SBP, DBP, MAP and HBR_M parameters for a synthesized oscillometric trapezoidal pulse envelope with SBP = 120 mmHg, DBP = 80 mmHg, MAP = 100 mmHg and HBR = 90 b.p.m. when the maximum amplitude of the oscillometric pulses (AMP) varies between 1 mmHg and 6 mmHg. BP monitor can also generate regulated pressure signals in the range between 10.0 and 400.0 mmHg with an accuracy of \(\pm\)0.5 mmHg and has a resolution of 0.1 mmHg. Figure 10 depicts the test setup that was used to calibrate the home blood pressure monitor. The set of parametrizations used for the comparative performance evaluation between the BP calibrator prototype and the commercial and certified BP calibrator includes the following set of values for systolic and diastolic pressures and HBR: 30-15-22; 60-30-40; 80-50-60; 100-65-77; 120-80-93; 150-100-117; 200-150-167 and 255-195-205, respectively. Figures 11 and 12 represent the experimental results that were obtained for the six values of systolic BP. From the calibration results, it is possible to see that regarding the calibration errors obtained by the commercial and certified BP calibrator, the maximum absolute error is lower than 2 mmHg, which corresponds to a maximum relative error almost equal to 1.4% relative to the pressure measurement range that is equal to 140 mmHg.