Description:
Used to Retrieve/Set the different available controls for the L-BAND Modulator component. (NTC70xx/NTC71xx/NTC72xx series).
Form:
Command Handler: SYSD
- To Retrieve all settings
LBANDMODULATOR | LBM | LM
- To Test connectivity
LBANDMODULATOR | LBM | LM PING
- To Retrieve a single setting
LBANDMODULATOR | LBM | LM ARG
- To set a single setting
LBANDMODULATOR | LBM | LM ARG VALUE
Arguments Description:
0- Transmit:
Allows the operator to enable or disable the Main RF output. If Transmit is enabled and any value for
Modulation Type, Frequency, Rolloff, Symbol Rate, or Interface Rate is changed, then Transmit will
be automatically disabled, however, the monitor output will remain active. This setting is ignored
on power up and starts in "Disabled" mode.
1 - Power:
Allows the operator to configure the output power of the main RF output port. The EN-XX IF has a
RF output power range from -30dBm to +5dBm, the EN-XX L-Band has a RF output power range from
-50dBm to -7dBm, and the EN-XX IF/L-Band has an RF output power range from -35dBm to +5dBm.
The monitor output power level for the EN-XX IF and L-Band is fixed at -45dBm.
Power is defined as the composite power referenced to an unmodulated (Pure Carrier) carrier.
2 - OccuppiedBandwidth (Read-Only):
Calculates and displays the bandwidth being used in real-time.
3 - Type:
Allows the selection of DVB-S or DVB-S2.
4 - Mode:
This control allows the operator to select the desired modulation mode and FEC code rate. The options
are dependant upon the feature key that is enabled.
5 - Frequency (Read-Only):
Allows the operator to view the output frequency of the main RF output port. The EN-XX IF
has a RF output frequency range from 50MHz to 180MHz and the EN-XX L-Band has a RF output frequency
range from 950MHz to 2.15GHz. The EN-XX IF+L-Band unit can output in both of these ranges. The monitor output
frequency for the EN-XX IF or EN-XX IF+L-Band when operating in IF is fixed at 1.080GHz.
The monitor output frequency for the EN-XX L-Band or EN-XX IF+L-Band when operating in L-Band tracks with the main RF output frequency.
6 - SpectrumInversion:
The Spectrum Inversion options are either Direct or Invert. If Direct is selected, then spectrum
inversion does not occur. Spectral inversion can occur when either the baseband signal is upconverted
to an IF frequency or when the IF is upconverted to the desired RF output frequency. Consider a 70MHz
IF signal with 10MHz BW (65MHz to 75MHz) that is mixed with a 1.0GHz local oscillator. With the high
sideband filtered, the RF output (low side) is then considered, by definition, to be inverted. Inversion
can be realized by calculating the band edges; 1.0GHz – 65MHz = 935MHz and 1.0GHz – 75MHz = 925MHz.
Spectrum Inversion occurred because the low side of the IF signal (65MHz) was translated to the high
side (935MHz) of the RF output signal.
7 - RatePriority:
The Rate Priority control allows the operator to designate which rate will be kept constant. When the
Symbol Rate is entered and Rate Priority is Symbol, the symbol rate is held constant and the Interface
rate is calculated. When the Interface Rate is entered and Rate Priority is Interface, the interface rate
is held constant and the symbol rate is calculated.
8 - SymbolRate:
The number of symbols transmitted per second. The amount of data per symbol is dependant upon the
modulation type, e.g. QPSK, 8PSK, etc.
9 - InterfaceRate:
The Interface Rate is the bit rate at the baseband interface.
10- RollOff:
The Rolloff selection will determine the shape of the output filter. The occupied bandwidth of the
modulated signal is the symbol rate multiplied by (1+α) where alpha (α) is the rolloff factor. By using a
lower alpha, carriers can be spaced closer together on a given transponder or an increased symbol rate
can be realized for a given bandwidth. The EN-XX IF/L-Band has options 35%, 25%, 20%, 15%, 10%, and 5%.
11- Pilot:
When operating in DVB-S2, the Pilot options are either ON or OFF. The DVB-S2 specification allows for
the option of inserting bursts of pilot tones that are very robust and prevents the carrier recovery system
from failing prematurely. However, when pilots are enabled, the total data throughput is reduced by
approximately 3.0%.
12- FecFrameType:
When operating in DVB-S2, the Frame Type options are either Normal or Short. The Normal 64,800-bit FEC frame
provides better protection but introduces more latency compared to the Short 16,200-bit FEC frame. Therefore,
the Short FEC frame type should be selected in applications where latency is critical and the longer frame
type should be used to optimize protection.
13- CarrierMod:
The Carrier Mode control allows the operator to select ON for normal operations or select one of four
unmodulated carriers. The Pure Carrier option will provide an unmodulated output carrier at the desired
frequency and output power. Other Carrier Mode options include Clock 4/8/16.
14- LocalOscillator:
The Local Oscillator (L.O.) control specifies the frequency of the local oscillator. The value for the
L.O. frequency is used with the Uplink frequency to calculate the L-Band or IF-Band frequency.
15- RfFrequency:
The RF Frequency control specifies the satellite uplink frequency. The value for the Uplink frequency is used
with the Local Oscillator frequency to calculate the L-Band or IF-Band frequency.
20- LbandFreq:
The L-Band frequency control specifies the modulator board's L-band frequency output.
The EN-XX IF/L-Band has has a range of 950MHz to 2150MHz.
21- IfFreq:
The IF-Band frequency control specifies the modulator board's IF-band frequency output.
The EN-XX IF/L-Band has has a range of 50MHz to 180MHz.
22- IfOutputImp:
Allows the user to specify the output impedance selection for the IF modulator board (50 or 75 Ohm).
Argument list:
0 - Transmit
1 - Power
2 - OccuppiedBandwidth (Read-Only).
3 - Type
4 - Mode
5 - Frequency (Read-Only)
6 - SpectrumInversion
7 - RatePriority
8 - SymbolRate
9 - InterfaceRate
10- RollOff
11- Pilot
12- FecFrameType
13- CarrierMod
14- LocalOscillator
15- RfFrequency
16-
17- UplinkMode
18- RefClk
19- RefClkComb
20- LbandFreq
21- IfFreq
22- IfOutputImp
Response:
"OK\r\n" to acknowledge receipt of command, and
[Reply Info] if required by the command
"ERROR- [Description]\r\n" if error, ending command
"\r\n" concludes modify responses (empty line)
Examples:
Show all settings:
LBANDMODULATOR | LBM <enter>
Response is:
OK
Transmit= DISABLED
Power= -30.0
OccuppiedBandwidth= 6.25
Type= DVB-S2
Mode= QPSK-3/4
Frequency= 80
SpectrumInversion= NORMAL
RatePriority= SYMBOL
SymbolRate= 5
InterfaceRate= 7.437365
RollOff= 25%
Pilot= OFF
FecFrameType= NORMAL
CarrierMod= ON
LocalOscillator= 40
RfFrequency= 120
UplinkMode= INVERT
RefClk= N/A
RefClkComb= N/A
LbandFreq= 1020000000
IfFreq= 80000000
IfOutputImp= 50
LM <enter>
Response is:
0 -30.0 6.25 5 13 80 1 1 5 7.437365 2 0 1 1 40 120 2 N/A N/A 1020000000 80000000 0
Show a single setting:
LBANDMODULATOR SymbolRate <enter>
Response is:
SymbolRate= 10000000
LM SymbolRate <enter>
Response is:
10000000
Set a single argument
LBANDMODULATOR | LBM | LM Transmit
Terse | Verbose | Description
0 Disabled RF Output from Modulator is disabled.
1 Enabled RF Output from Modulator is enabled.
Response is: OK\r\n
LBANDMODULATOR | LBM | LM Type
Terse | Verbose | Description
3 DVB-S Modulation Type is set to DVB-S
5 DVB-S2 Modulation Type is set to DVB-S2
Response is: OK\r\n
LBANDMODULATOR | LBM | LM Mode
Terse | Verbose | Description
11 QPSK-1/2
12 QPSK-2/3
13 QPSK-3/4
15 QPSK-5/6
16 QPSK-6/7
17 QPSK-7/8
21 QPSK-1/4
22 QPSK-1/3
23 QPSK-2/5
24 QPSK-3/5
25 QPSK-4/5
26 QPSK-8/9
27 QPSK-9/10
42 16APSK-2/3
43 16APSK-3/4
44 16APSK-4/5
45 16APSK-5/6
48 16APSK-8/9
49 16APSK-9/10
53 32APSK-3/4
54 32APSK-4/5
55 32APSK-5/6
58 32APSK-8/9
59 32APSK-9/10
63 16QAM-3/4
67 16QAM-7/8
81 8PSK-3/5
82 8PSK-2/3
83 8PSK-3/4
85 8PSK-5/6
88 8PSK-8/9
89 8PSK-9/10
Response is: OK\r\n
LBANDMODULATOR | LBM | LM SpectrumInversion
Terse | Verbose | Description
1 NORMAL Spectrum Inversion is Disabled.
2 INVERT Spectrum Inversion is Enabled.
Response is: OK\r\n
LBANDMODULATOR | LBM | LM RatePriority
Terse | Verbose | Description
0 INTERFACE Interface Rate takes priority.
1 SYMBOL symbol Rate takes priority.
Response is: OK\r\n
LBANDMODULATOR | LBM | LM SymbolRate <Rate> <enter> #
Response is: OK\r\n
LBANDMODULATOR | LBM | LM InterfaceRate <Rate> <enter> #
Response is: OK\r\n
LBANDMODULATOR | LBM | LM Rolloff
Terse | Verbose | Description
1 35 Sets Roll-off factor to 35%
2 25 Sets Roll-off factor to 25%
3 20 Sets Roll-off factor to 20%
4 15 Sets Roll-off factor to 15%
5 10 Sets Roll-off factor to 10%
6 5 Sets Roll-off factor to 5%
Response is: OK\r\n
LBANDMODULATOR | LBM | LM Pilot **
Terse | Verbose | Description
0 OFF DVB-S2 Physical Layer Pilot insertion is disabled.
1 ON DVB-S2 Physical Layer Pilot insertion is enabled.
Response is: OK\r\n
LBANDMODULATOR | LBM | LM FecFrameType **
Terse | Verbose | Description
0 SHORT FECframes of 16200 bits or 2025 bytes. Greater overhead but shorter encapsulation delay.
1 NORMAL FECframes of 64800 bits or 8100 bytes. Lower overhead but longer encapsulation delay.
LBANDMODULATOR | LBM | LM CarrierMod
Terse | Verbose | Description
0 PURE_CARRIER Use for unmodulated output signal
1 MODULATED Use for operational modulated carrier signal
2 CLOCK/8 (NTC70XX/NTC71XX only) Test Modulation. Carrier modulated by a rotating vector with a period of BaudRate/8.
4 CLOCK/4 (NTC70XX/NTC71XX only) Test Modulation. Carrier modulated by a rotating vector with a period of BaudRate/4.
5 CLOCK/16 (NTC70XX/NTC71XX only) Test Modulation. Carrier modulated by a rotating vector with a period of BaudRate/16.
LBANDMODULATOR | LBM | LM IfOutputImp
Terse | Verbose | Description
0 50 Output impedance selection is set to 50 Ohm.
1 75 Output impedance selection is set to 75 Ohm.
Response is: OK\r\n
Notes:
# The actual range depends on installed hardware and software capability.
** Only available on DVB-S2 Modulation Type