Assignment:
Consider a radio transmission system (narrowband channel model) where the transmit antenna has a gain of 10 dB and the receive antenna of 7 dB. The receive antenna is modeled by a resistance with noise temperature 120 K. In cascade with the antenna we have an amplifier with gain 20 dB and noise figure 7 dB. Consider the receiver matched for the maximum power transfer. The carrier frequency is 500 MHz and the information signal has a bandwidth of 5 MHz.
a) Determine the noise power density (in dBm/Hz) at the receive amplifier output.
b) In the case the distance between transmitter and receiver is 300 m, determine the transmit power (in dBm) required in order to get an output SNR of 20 dB.
c) Determine the maximum distance to guarantee an output SNR of 20 dB if the transmit power is 10 dBm.