Planar IT-088, Operating Manual

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g) Modulat: type of modulation (for channels with digital modulation). The following
values are available: ------ , QAM16 , QAM32 , QAM64 , QAM128 , QAM256, COFDM-
QPSK, COFDM-QAM16, COFDM-QAM64. «------» value indicates unknown type of
modulation or its absence.
DVB-C Channel Parameters:
a) Symb rate: symbol rate (for channels with digital modulation). The values available
from 1.000 to 7.200 Msps.
DVB-T/H Channel Parameters:
a) Spectrum : the type of DVB-T/H channel spectrum (inverted/normal). The values
available: norm , inv ;
b) DVB bandwidth: DVB-T/H channel bandwidth. The values available: 6MHz , 7MHz ,
8MHz;
c) Subcarriers: number of subcarriers in the DVB-T/H channel. The values available:
2k , 4k , 8k ;
d) Guard interval: the value of guard interval of DVB-T/H channel. The values
available: 1/32 , 1/16 , 1/8 , 1/4 ;
e) Hierarch mode: the mode of hierarchical modulation of DVB-T/H channel (only for
channels with COFDM-QAM16 and COFDM-QAM64 modulation). The values available: - ,
α =1 , α =2 , α =4 ;
f) FEC (HP): forward error correction factor of the high-priority data stream. The values
available: 1/2 , 2/3 , 3/4 , 5/6 , 7/8 ;
g) FEC (LP): forward error correction factor of the low-priority data stream. The values
available: 1/2 , 2/3 , 3/4 , 5/6 , 7/8 .
The initial values of the parameters are set during the automatic detection of the
channel plan and can be manually edited by the user by means of frequency point editing
function or can be determined automatically by automatic adjustment function (
F3 ).
When you create a new channel plan (section 4.4.2.4), set the following values of the
channel parameters.
For analogue channels set the frequency to the video carrier value. The noise
measurement frequency should be set 500 kHz lower than that of the audio carrier.
For digital channels set the frequency to the central frequency of the current channel
band. The noise measurement frequency and the frequency bandwidth should be set in
accordance with the TV system being used. If measurement parameter setting function
(section 4.3.10) allows scanning DVB-T/H digital channels, then for such channels
modulation type and symbol rate should be set. If you do not set these parameters, they
will be defined during automatic tuning to the particular digital channel.
To fine tune a parameter, select it by « », « » keys, and then scroll to the required
values by « ◄ » , « ► » keys, or enter them using the keypad.
For accurate automatic setting of the frequency point, set the channel number and its
status (analogue or digital). Press «F3» ( Setting ). The signal will be given to the input of
the Analyzer, which will analyze it and set the optimal channel parameters. To save the
frequency point, press
«F2» ( Save ). To abort the function without saving changes, press
«F1» ( Exit ). If the reception quality is poor, when e.g. ripple of the digital channel is higher
than 3 dB, the automatic tuning can be incorrect. In any case, check all the parameters
after the channel plan has been set. It is more convenient to determine the parameters in
the spectrum measurement mode by means of a PC. In case of incorrect (or non-optimal)
settings, fine tune the parameter manually. Otherwise it can lead to errors in channel
parameters measurements or in operations with Data Loggers.