Consider a communication system that converts a digital signal to analog form for transmission, then recovers the digital signal at the receiving end. Another system starts with an analog signal, which it then converts to digital form for transmission, and recovers the analog signal at the receiving end. Both systems require both A-to-D and D-to-A conversion, yet one system is considered more reliable than the other. Which one? Why? Compare the A-to-D-to-A communication system with one that is entirely analog. What are the important factors affecting the performance of each system?