For each of the sensors the frequency was measured. An example of the results for 36 sensors, plotted by Gnuplot, and interpolated results from Scilab are shown in Fig.5 and Fig.6. In this case, the frequency results from the implemented ring oscillators can’t directly represent the temperature inside the tested structure. Although all ring oscillators were identical (the same inverters were implemented in CLBs), they were placed in differ parts of the FPGA area