Hitachi CL2554AN, Руководство по обслуживанию

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Service manual CL2554AN / CL2854AN
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1-3 ATSS sorting method
The TV set sweeps all the TV bands from beginning of VHF to end of UHF. The TV
controlling software for each program checks if a VPS CNI code is transmitted. If no VPS CNI
code is found, the system check if a CNI code is transmitted in the teletext lines ( Packet 8/30
format 1 ). If such a code ( VPS or teletext ) is found and if this code is in the ATSS list, the
program is automatically named.
The programs found are then sorted in 4 groups :
Group I : It contains all the programs from the selected country and named by the TV
controlling software. Within this group the sorting order is fixed by the ATSS list.
Group II : It contains all the programs with a strong signal strength which are not listed in
group I.
Group III : It contains all the programs with a weak signal strength which are not listed in
group I.
Group IV
: If two or more programs with the same code are found, only the strongest ( or if
they have the same level the one with the lowest frequency) is listed in group I, II or III. The
others are listed in group IV. Note : If two programs with the same name but a different code
are found these two programs are listed in group I, II or III ( e.g. Regional program SW3 in
Germany ).
The sorting order within group II, III, and IV is based on the channel frequency. The program
with the lowest frequency is allocated the first rank in its group, and so forth until the last
program of the group which has the highest frequency.
Program
number
Group Skip
1
2 Group I
...
n
n+1
... Group II
m
m+1
... Group III
p
p+1
... Group IV 4
q
q+1 not used
... 4
99
0
Program
number
Group Skip
1
... Group II
m
m+1
... Group III
p
p+1
... Group IV
4
q
q+1 not used
...
4
99
0
Special case :
Country selection = Others
Special case : France
If France is selected the TV controlling software sweeps the whole TV bands firstly with France
system selected ( positive video modulation) and secondly with Europe system selected ( negative
video modulation).