Assume that you are a design engineer in a defense technology company and given the task of analyzing the building blocks of a design that was previously established one of the former engineers of the company. The design consists of a set of cascaded blocks starting from microphone, analog-to-digital converter (ADC), source encoder, and an unknown block, say block X, followed by the mixer. Also, there is a perfect physical prototype of the design, which is "claimed to be still in operation. Due to some issues, somehow, only the documentation belonging to block X is lost and cannot be retrieved; however, all other documentation peculiar to other blocks are perfectly preserved and could be accessed. Therefore, you are asked to characterize block X. Furthermore, you are asked to check whether the prototype is operational and if yes, the output makes sense. Devise a method for the task you are given and explain your reasoning