From a source with Pin = 2.4 mW, we want to get Pout = 60 mW at a distance l = 20 km from the source. α for the transmission line is given to be 2.3 dB/km. The available amplifiers have adjustable power gain, but are subject to two limitations: (i) the input signal power must be at least 1 µW to overcome internal noise, and (ii) the output signal power must not be greater than 1 W to avoid nonlinear distortion. Design an appropriate system.