Radyne ComStream TIERNAN SE4000, Installation And Operation Manual

Page: 83 / 161

Using a Remote Unit SE4000 MPEG-2 Contribution Encoder
4-18 01-0934-401-B
SE4000 Remote Command Descriptions
Remote Command Parameter
Range
Factory
Default
Description
MOD SYM_RATE MOD SR
1000000 to
20000000 sps
- Used to enter the modulator symbol rate. The
symbol rate is the number of symbols required to
transmit the data stream over a satellite link using
quadrature phase shift keying (QPSK). The
symbol rate is a function of the data rate and the
code rate, including any overhead. The symbol
rate may be entered directly by issuing a MOD_SR
command or will be automatically computed based
upon the entered data rate and code rate. The
symbol rate is equal to the Data Rate x 1/2 x
204/188 x 1/V, where V = the Viterbi code rate.
When the code rate is entered, the data rate
remains unchanged, however, the symbol rate is
recomputed.
If the displayed symbol rate exceeds the allowable
satellite bandwidth, the data will be corrupted
during transmission. To determine the satellite
bandwidth required to transmit the displayed
symbol rate, use the following equation:
symbol rate x 1.35 = required satellite bandwidth
(measured in Hz)
Front panel command equivalent:
Config>Output>SymRate
MOD CF 52000000 to
88000000 Hz,
104 MHz to
176 MHz, 950
MHz to 2050
MHz in 1 Hz
increments
70000000
Hz
Used to set the modulator carrier frequency. The
acceptable range of options is implemented with a
pass band filter that filters out all frequencies below
and above the range. When selecting a carrier
frequency, you must take into account the satellite
bandwidth required for transmission. If you select a
carrier frequency that is too close to either end of
the valid range, data may be clipped by the pass
band filter. For information on calculating the
satellite bandwidth, see the MOD SR command.
Front panel command equivalent:
Config>Output>Tx Freq
MOD POW -2500 to 0
dBm in 0.1 dB
increments
-500 dBm Modulator power set in hundredths of dBms.
-2500 = -25.00 dBm
MOD ENABLE ON/OFF
MOD TYPE DVB_QPSK,
8PSK, 16QAM
DVB_QPS
K
MOD TERR_TYPE NONE,
DVB188,
DVB204
DVB_188 Sets the framing mode for the ASI output stream
MOD RATE_CTRL SYMBOL_RATE,
DATA_RATE,
NONE
SYMBOL_
RATE
Sets the “master rate s etting mechanism for the
modulator
SYMBOL_RATE = symbol rate is settable – data
rate is calculated and read only
DATA_RATE = Data rate is settable – symbol rate
is calculated and read only
AUTO = Both data rate and symbol rate are
settable and the other is calculated
MOD
MOD_ROLLOFF 20, 25, 35 35 Modulator roll off factor
35 = 0.35 DVB standard
20 = 0.20
25 = 0.25