Operation Manual

SFX SERIES USER’S GUIDE
Rev 2.2 19
Carrier Type
S S
Auto
Viterbi
S2 S2
Auto
RF Metric Description
marginally too high (80% to 89%).
Green – signal level is in the acceptable AGC operating range
(30% to 80%).
■ ■ Eb/No This value represents the calculated Eb/No (in dB) at the input to
the tuner. This value is derived from the C/N value, with
compensation for modulation scheme, Reed-Solomon FEC, Viterbi
FEC rate, and symbol rate of the carrier.
■ ■ ■ ■ C/N This value represents the estimated carrier to noise ratio (in dB) at
the L-Band input to the tuner. The format of this value is x.y dB.
■ Mod Standard Selects the modulation standard as either DVB-S or DVB-S2
■ Viterbi Rate This is the factor used in the FEC of the satellite data for recovery
of data.
■ Code Rate
■ Alpha Factor
■ ■ Viterbi BER This is the number of bit errors encountered during a fixed frame
length of incoming data. This data is obtained from the tuner
demodulator chip and is converted to a BER value in the form x.y
E -z.
■ ■ ■ ■ LNB Offset This indicates what the current LNB offset is, based on the
automatic LNB drift tracking mechanism of the tuner. This value is
added or subtracted from the set frequency in the DVB Carrier
definition to tune to the carrier.
■ ■ ■ ■ Refresh Shows the period of the refresh of the RF metrics on this page.
NOTE: The accuracy of the values reported for C/N and Eb/No are typically ±1 dB up to a C/N of 15 dB (BER of 1 x
10
-12
). With C/No values higher than 15 dB, the accuracy degrades. (For example, a DVB-S signal can be considered
error free at greater than 7 dB Eb/No at 7/8 Viterbi, 4 dB Eb/No at 1/2 Viterbi).
Controlling the Receiver with SNMP
The Simple Network Management Protocol (SNMP) is a set of protocols for managing complex networks. SNMP
works by sending messages, called Protocol Data Units (PDU’s), to different parts of a network, providing a standard
mechanism for network control and monitoring. SNMP-compliant devices, called agents, store data about themselves
in Management Information Bases (MIB’s) and return this data to the SNMP requestor.
The advantage of using SNMP is that its design is simple, hence it is easy to implement on a large network. It does not
take a long time to set up, puts very little stress on a network and is easy for users to program. Its simple design also
allows it to be easily updated so that it can expand for future network requirements.
SNMP has been implemented in the SFX Series satellite receivers to provide users with flexibility in network
management.