DVB-S2 system is the second generation system for broadcasting of digital TV signals by…
DVB-S2 system is the second generation system for
broadcasting of digital TV signals by geostationary satellites at 12 GHz carrier
frequency. The satellite transmitter, at 42000 km away from the earth surface,
is assumed to have an EIRP = 51 dBW. Nyquist filtered and 3 /4 encoded symbol
rate of QPSK signals is 30.9 Msymbols/s. The ground station receiver has a
diameter of 0.6 m and 65 % aperture efficiency.
a. Determine the raw (useful) bit rate at the satellite. If
standard TV (SDTV) signals are broadcasted at approximately 4 Mbps, how many
SDTV channels can be multiplexed in this system?
DVB-S2 system is the second generation system for
broadcasting of digital TV signals by geostationary satellites at 12 GHz carrier
frequency. The satellite transmitter, at 42000 km away from the earth surface,
is assumed to have an EIRP = 51 dBW. Nyquist filtered and 3 /4 encoded symbol
rate of QPSK signals is 30.9 Msymbols/s. The ground station receiver has a
diameter of 0.6 m and 65 % aperture efficiency.
a. Determine the raw (useful) bit rate at the satellite. If
standard TV (SDTV) signals are broadcasted at approximately 4 Mbps, how many
SDTV channels can be multiplexed in this system?
b. This system requires a C/N power ratio of 5.1 dB at the
Earth-based satellite receiver in a 27.5 MHz bandwidth. Determine the maximum
allowed noise temperature of the receiver system.
c. If the antenna noise temperature is 147 K, then determine
the noise figure of the receiver system.
d. Now assume we use a low-noise amplifier (LNA) just after
the receiver antenna with 20 dB gain. Determine the noise figure of this LNA if
the rest of the receiver system has an equivalent noise figure of 10 dB.
e. How the link budget is altered when there is a rain, with
physical temperature of 290 K, causing 3 dB signal loss? How can you overcome
this problem?
