Promax HD RANGER, Руководство пользователя

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A1.1.5
Digital SATELLITE television signal of SECOND generation
(DVB-S2 standard / QPSK/8PSK modulation)
A1.1.5.1 DVB-S2 Parameters
►
Channel Bandwidth
It displays the channel bandwidth from 1.3 MHz to 60.75 MHz. This
parameter affects the frequency separation of the carriers.
►
Spectral inversion
It detects if the input signal has been inverted.
►
Symbol Rate
It represents the number of times the signal status changes in a period of
time. The bandwidth is related to this parameter.
►
Roll-Off Factor
Roll-off factor of Nyquist filter. It indicates the excess of bandwidth over the
ideal bandwidth.
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Constellation
COFDM modulation with constellation QPSK, 8PSK.
►
Code rate
Also known as Viterbi ratio. It defines the ratio between the number of data
bits and the total number of bits transmitted (the difference corresponds to
the number of control bits for the error detection and recovery). The value
will be between 1/2, 2/3, 3/4, 5/6 and 7/8.
A1.1.5.2 DVB-S2 Measurements
Power
Channel power, assuming that power spectral density is uniform over the
entire bandwidth of the channel.
C/N
(Carrier / Noise) where C is the received power of the modulated carrier
signal and N is the noise power received. To measure it correctly the channel
should be tuned at its centre frequency.
August 2012
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