Question:
Figure 15.3 shows a communication system. What is the output power when the input signal is of 1.01mW? (gain in dB = 10 log10 (Po /Pi ).
Solution:
Loss suffered in the path of transmission = 2 dB/km
Distance travelled by the signal = 5 km
Total loss suffered = -10 dB
Totla amplifier gain = 30 dB
Overall gain in signal = 20 dB
Gain in dB = 2
Input power = 1.01 mW
Po = 1.01 × 100
Output power is 101 mW.