3. A simplified block diagram for a radio system, such as a cell phone, is shown below. The signal transmission part of the system is enclosed by the red box in

the diagram. PA stands for Power Amplifier, which amplifies an input signal to drive the antenna. You can think of it as linear amplifier for signals within a specific narrow band of frequencies. Describe the chain of events starting from the input analog voice signal (marked A in the diagram) to the output signal at the antenna in terms of how signals are transformed at the output of each major functional block inside the transmitter. Draw signals or their spectrum shape at the output of each functional block inside the red-boxed area to illustrate how signals are transformed in the process. Antenna Diplexer Antenna & Propagation BPF BPF LO Power Supply & Management PA Mixer LNA Mixer RF Frontend Amp Amp A LPF A/D and D/A Converters and Filters Baseband Backend Video 1/0 Audio 1/0 storage