Chapter 10 - Upstream Generator
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Upstream Generator
Chapter 10
The Upstream Generator can be used during analysis of the return channel range (5 MHz to 65
MHz). One or four carriers can be transmitted in that range. The Upstream Generator usually acts
as modem, the transmitted signals could be analyzed by the head end equipment (e.g. CMTS).
From DOCSIS-3.1-Analyzer it is possible to send up to 8 single carrier (CW, QAM-modulated) or
one OFDM modulated carrier. The frequency range can be choosen between 5 to 85 MHz and 5 to
204 MHz, depending on the diplexer setup (17.14 - DOCSIS3.1 Setup the maximum
The carrier(s) is/are transmitted unmodulated as a pure sinusoidal signal, or modulated as a PRBS
signal (pseudorandom binary sequence). A sinusoidal signal can be used to gain information about
the incoming level strength, whereas a modulated signal can also be used to determine error rates,
i.e. MER and BER.
An adapted AMA310 / UPM 3500 / WA 71 type measuring receiver at the headend can therefore
be used to tune to a carrier in the return channel measuring range. Levels can be measured, MER
and BER can also be measured for modulated signals, the constellation diagram can be checked,
monitoring can be started or the DataGrabber can be used. If the measuring instrument in the head
end supports SNMP and it is connected with the network via LAN, the measurement results can be
analyzed directly at the Upstream Generator using a network-connected laptop running
AMA.remote software.
10.1
Upstream-Generator Version DOCSIS3.0
10.1.1
Starting and Profile Support
The Upstream generator is called up via
RANGE
->
Upstr. Gen.
.
Figure 10-1 Upstream Generator Measuring Range
Two configurable profiles are available for presetting of the transmit carrier(s). You can access the
configuration and transmission screen by selecting one of the profiles.
