155k views
4 votes
A GEO satellite transmits a signal in an 11700 MHz downlink channel. What is the path loss the signal experiences? If the EIRP is 40 dBW, and the receiver noise level is -125 dBm, what is the receive SNR if the earth station antenna gain id 60 dB? Can this system support high quality analog voice communications if the required SNR is 30dB

1 Answer

5 votes

Final answer:

The path loss of the GEO satellite signal can be calculated using the Friis transmission equation. The receive SNR can be calculated by subtracting the path loss, receiver noise level, and adding the Earth Station antenna gain from the EIRP. The system can support high-quality analog voice communications.

Step-by-step explanation:

The path loss experienced by a GEO satellite signal can be calculated using the Friis transmission equation:

Path Loss = EIRP - (20 log10d) + (20 log10f) + 147.55

  • EIRP is the Effective Isotropic Radiated Power in dBW, which is 40 dBW in this case.
  • d is the distance between the transmitter and receiver in kilometers.
  • f is the frequency of the signal in gigahertz, which is 11.7 GHz in this case.

Assuming a distance of 1000 km, the path loss would be:

Path Loss = 40 - (20 log10(1000)) + (20 log10(11.7)) + 147.55 = -158.45 dBW

The receive signal-to-noise ratio (SNR) can be calculated using the equation:

Receive SNR = EIRP - Path Loss - Receiver Noise Level + Earth Station Antenna Gain

  • The Receiver Noise Level is -125 dBm.
  • The Earth Station Antenna Gain is 60 dB.

The receive SNR would be:

Receive SNR = 40 - (-158.45) - (-125) + 60 = 82.45 dB

Since the required SNR for high-quality analog voice communications is 30 dB, this system can support high-quality analog voice communications.

User Slysid
by
7.5k points