In this experiment, we recorded a person saying "Aaaaaaa" on the mic as the analog source. And then the analog data was converted into digital data so that the programme in the PC could read it and then the digital data was converted into Analog again to reproduce the recorded voice. I attached the results of the last part of the experiment. I am not sure what method this is because it wasn't me who did this. What I do know is that he had to check whether the digital data was transmitted accurately or not by using the A/D and D/A conversion programme on the PC. Can someone explain to me what excatly does that picture mean? What is being done here?