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Chapter 10 - Upstream Generator
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10.2.2.7
Setting the symbol rate
For DOCSIS single QAM carriers following bandwidths are defined: 400 kHz, 800 kHz, 1.6 MHz,
3.2 MHz and 6.4 MHz. These correspond to the symbol rates 320 kBd, 640 kBd, 1,280 kBd, 2,560
kBd and 5,120 kBd. This setting can be carried out via the
SYMBOLRATE
menu item if modulation
is activated.
10.2.2.8
Setting the OFDM upstream bandwidth
If an OFDM carrier as transmit channel selected, then instead of
SYMBOLRATE
the
BANDWIDTH
button is available. You can enter a bandwidth between 6 and 96 MHz.
10.2.3
Saving Profile settings
The settings made are saved in the current used profile using the
SAVE
menu item.
10.2.4
Transmitting with Upstream-Generator Version 3.1
After the bootprocess is finished, the F-Key buttons
TRANSMIT
and
OFDM TRANS
are available.
With
TRANSMIT
all activated single QAM carrier will be transmitted (CW or modulated). With
OFDM TRANS
the OFDM channel will be transmitted. In the Status line the state will changed to
"TRANSMITTING…". Before the transmission starts, a crosscheck of the plausability of all carrier
settings will be performed. If the check fails, e.g. a parameter is out of its valid range, the
transmission will be canceld and an error messages tells you where the problem is. The settings
must be fixed before a transmission can be started.
It is not possible to send QAM and OFDM modulated carriers at the same time.
Attention: Before you initiate a transmission in the upstream frequency range, you have
to check if no active DOCSIS system can be interrupted. Select only frequency
ranges which are not used from an acitve DOCSIS system. Be carefully in
adjusting the bandwidth to avoid any interruptions between modems and
CMTS.
During transmitting carriers the F-Key button is shown inverted. A further pressing of that button
stops the transmission.
10.3
Telemetry channel
This video image can be transmitted using a previously saved analog or digital TV channel. If, for
example, the interface of a measuring instrument that evaluates signals transmitted by the
upstream generator is set to the telemetry channel using a video encoder, changed settings for the
generator can be checked at another location.
10.3.1
Saving the telemetry channel
A transmitter must be tuned in the TV range (analog or DVB-C).
Using the
MODE
button, you can access the
Save as telemetry channel
menu item.
As in the
Saving
section, pressing
ENTER
will open a menu that displays the currently stored
telemetry channel (see chapter 14.1 - Saving). Press
ENTER
to save it.
As with all tuning memory locations, you must confirm the overwriting process again. Only one
telemetry channel can be stored at a time, so no memory number is displayed.
