Topic: Satellite Communication
A satellite communication link has uplink C/N_0 of 50 dB-Hz and downlink C/N_0 of 47 dB-Hz. What would be overall link C/N_0?
- A. 44 dB-Hz
- B. 45 dB-Hz
- C. 48.5 dB-Hz
- D. 53 dB-Hz
Answer: B. 45 dB-Hz
Explanation: (C/N)_uplink = 50 dB-Hz = 10^5; (C/N)_downlink = 47 dB-Hz = 10^4.7. 1/CNR_overall = 1/CNR_uplink + 1/CNR_downlink. 1/CNR_overall = 1/10^5 + 1/10^4.7. So, CNR_overall = 33386.05. CNR (dB) = 45.23 dB-Hz.