Planar IT-14, Руководство по эксплуатации

Страница: 15 / 27

5 – perBER value
6 – postBER value
7 – erroneous packets after Reed-Solomon decoder counter
8 – command line with commands activated by
F1, F2 and F3 keys
9 – channel name (when working with selected channel plan)
10 – demodulator status.
When this mode is activated or tuning to a channel is performed, the Analyzer will start input signal
synchronization process, which will be indicated by a progress bar in position 10. The lock icon
will appear in position 10 once synchronization is achieved. Subcarrier modulation type and subcarriers
number will be presented in position 3. Some time later MER, preBER, postBER and erroneous packets
number measured values will appear in positions 4, 5, 6 and 7. If postBER value is lower than 2.0E-04, then
postBER marked with
«pass» message, otherwise with «fail» message.
If signal level value of the selected channel is insufficient, low level icon will be blinking in
position 10. Channel synchronization in this case is impossible. If signal level is high enough, but
sinchronization hasn’t been achieved in 30 secinds, then channel has too high noise level, or channel has
modulation other than DVB-T.
To measure channel parameters, select the required channel by ◄ and ► arrows.
If no channel plan is selected, using ◄ and ► arrows you can switch to any channel in accordance with
the selected channel template (Section 4.6). Once a signal is detected, the Analyzer will automatically
determine the channel parameters: frequency offset, spectrum inversion, subcarriers number, subcarriers
modulation type, guard interval and code rate.
If one of the channel plans has been selected, the tuning will be performed between the digital channels
of the channel plan. In this case, after entering MER/BER mode you will see selected channel plan name
indicated by
«Plan:» for a few seconds. The channel parameters will be taken from the channel plan. If the
selected channel plan does not include any digital channels, tuning to channels will not be performed.
NOTE!
When working with hierarchical modulated channel, postBER is measured for low priority stream.
When you press
, current measurement is interrupted and demodulator starts channel sinchronization
once again.
You can access other measurement modes using functional keys. F2 key will activate CONSTELLATION
measurement mode (Section 4.3.3) . F3 key will open LEVEL measurement mode (Section 4.3.2) .
Press
F1 key, if you want to get detailed information of channel parameters. Channel parameters table is
represented in the Figure 4.3.12.
Figure 4.3.12
On the scrren you will see the following parameters:
a)
DVB bandwidth – channel bandwidth;
b) Spectrum – spectrum type: inverted or normal;
c) Guard interval – guard interval relative duration;
d) Hierarch mode – hierarchical modulation mode;
e) Code rate (HP) – high priority stream relative code rate;
f) Code rate (LP) – low priority stream relative code rate (for hierarchical modulation only);
g) TPS cell ID – transmitter ID in hexadecimal format.
Press
key to return to MER/BER measurement mode.
15