Attenuation (example)
If the power of the transmitted signal 400 W and the power of the received signal is 100 W, the attenuation is
10 log10 (St / Sr) dB = 10 log10 (400 / 100) dB = 6 dB
If a signal is attenuated and amplified at different legs of a transmission, the attenuations and amplifications can be summed in dB. Say the signal is attenuated 4 dB then amplified 3 dB and then attenuated 2 dB, the total is
- 4 dB + 3 dB - 2 dB = - 3 dB
Thus the signal is attenuated by 3 dB, that is to half of its original power.