Tiernan DBR3000, Installation And Operation Manual, Page: 53 / 74

Maintenance and Troubleshooting
LT LNB Type
Syntax: LT n
LT ?
The LNB-type command allows the user to select a mode in which the receiver automatically selects the LNB
type.
The selection of the proper LNB type modifies receiver parameters that are needed to perform carrier tracking
properly. The two types of LNBs that are used at the remote site system are DRO and PLL. A value of 0 for
n
configures the receiver for a DRO-type LNB, whereas a value of 1 for n configures the receiver for a PLL-type
LNB.
A value of 2 for n instructs the receiver to automatically select the type of LNB. The receiver uses the current
modulation type, as specified in the LTD command, to determine for which LNB type to configure. If the current
modulation type is BPSK, the receiver configures for a DRO-type LNB, whereas if the modulation type is QPSK,
the receiver configures for a PLL-type LNB. The receiver automatically selects the LNB type prior to every RF
acquisition attempted.
The default value for LT is 0.
LTA Link Table Acquire
Syntax: LTA A
LTA B
LTA ?
This command is used to instruct the DBR to acquire Link Table A or B as defined by the LTD command. When
attempting to acquire a new Link Table when the DBR is already locked to an existing Link Table, the time defined
by LTW is adhered to before the acquisition is attempted.
LTD Link Table Define
Syntax: LTD Table_n,DR_nnnn,RF_nnnn,RM_n,RC_n,RSC_n
LTD Table_n
LTD ?
This command is used to instruct the DBR to acquire Link Table A or B as defined by the LTD command. When
attempting to acquire a new Link Table when the DBR is already locked to an existing Link Table, the time defined
by LTW is adhered to before the acquisition is attempted.
Table 5.5
Parameter Descriptions
Parameter Description
Table_n Table to be configured. Valid tables are A and B.
DR_nnnn Specifies the receive data rate (bits/sec). Valid data rates are between: 64000 and 448000
depending on the values of RM and RC.
RF_nnnn •
Specifies the RF input frequency to be received. The range of valid receive frequencies are:
•
L-band 950000 kHz to 1750000 kHz
•
C-band 3.7 to 4.2 GHz
•
Ku-band 10.95 to 11.699 GHz, 11.7 to 12.2 GHz, and 12.25 to 12.75 GHz
•
All values are entered in increments of 1000 Hz (1 kHz). For:
•
Ku-band: 8 digits for nnnn
•
C-band: 7 digits for nnnn
RM_n Specifies the receive modulation type: 0 = BPSK, 1 = QPSK
RC_n Optional field; specifies the inner convolutional coding rate and method. 1 = rate ½ Viterbi; 2 = rate
rate 2/3 Viterbi; 3 = rate 3/4 Viterbi; 5 = rate 5/6 Viterbi; 7 = rate 7/8 Viterbi; 8 = rate 1/2 Sequential;
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