Promax US TV EXPLORER II, Руководство пользователя

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USER’S MANUAL. US TV EXPLORER II
Page 62 01/2008
PER: 0
MHz
kHz
MHz
MPEG-2 TS
FREC:
DL-Ku:
CAN:
C/N:
POTEN.:
MER:
CBER:
BER: » L
16.1
69.8
12.6 dB
dBµV
dB 2121.97
12722.0
-1657
119 1.1E-1
2.7E-7
ELAPSED TIME: 00:00:05
Figure 42.- DVB-S2 ( QPSK/8PSK ) signals LBER measurement screen.
The DSS (Direct Satellite System) is a video and audio distribution system to
broadcast digital TV over Ku -Band and C -Band. The DSS utilizes QPSK modulation,
with 127-byte packets and the Viterbi and Reed-Solomon algorithms for error detection
and correction, with variable
FEC rate to squeeze the maximum available bandwidth out
of each satellite transponder. The DSS systems typically utilize a video encoding
scheme very similar to, but not compatible with, the final MPEG-2 standard.
The DSS is a type of DBS (Direct Broadcast Satellite) system, which are also
referred to as mini-dish systems, because they use smaller (18") dishes than the
previous generation of C Band systems.
FREQ:
CH:
C/N:
POWER:
MER:
CBER:
VBER: »
0.2
51.5
10.9
dB
dBµV
dB MHz
kHz
MHz
1936.01
11686.0
---
32
-8 -7 -6 -5 QEF -4 -3
9.7E-4
5.2E-8
MPEG-2
Figure 43.- Screen of VBER measurement ( DSS signals).
The BER measurement is provided in scientific notation (i.e. 2.0 E-3 means
2.0x10
-3
, that is to say two incorrect bits of every 1000) and through an analogue bar (as
its length is smaller the signal quality will be better). The analogue representation is
done on a logarithmic scale (not linear).