Tiernan DBR3000, Installation And Operation Manual, Page: 47 / 74

Maintenance and Troubleshooting
Table 5.3
Acquisition Type, Action, Status
Type Action Status
0 Disable acquisition Acquisition disabled/complete
1 Initiate fade acquisition Fade acquisition in progress
2 Initiate power-on acquisition Power-on acquisition in progress
A fade acquisition is automatically initiated whenever RF sync is lost while the receiver is locked onto a carrier.
During a fade acquisition the DBR concentrates its search for the RF carrier at the frequency where it last
achieved RF sync, based on the B1 and B2 values.
A power-on acquisition occurs any time the DBR is power cycled. A power-on acquisition begins its search for the
RF carrier at the start acquisition frequency. The start acquisition frequency is calculated by the DBR using the
value of the RF parameter defined in the link table definition (LTD) command. The offset value specified in the
acquisition offset (AO) command is also added to the calculated start acquisition frequency.
A detailed description of the DBR binning and acquisition processes can be found in the chapter on Functional
Description and Theory of Operation.
B1 Primary Search (Binning) Range
Syntax: B1 ?
The B1 command is a query-only command that returns the value of the frequency range that will be searched for
the primary (B1) bin. The value of this parameter is determined by the symbol rate and is given in units of kHz.
B1 and B2 are used together. When performing fade acquisition, the B1 range is searched first for the carrier
signal. If the carrier is not found in the B1 range, the range indicated by the B2 parameter is searched above and
below the B1 range. After the search of a B2 range, the B1 range is searched again.
When all B2 ranges have been searched within the user-specified acquisition range limit (B3) without finding the
carrier, the search pattern is repeated from the beginning. A detailed description of the DBR acquisition process
can be found in the chapter on Functional Description and Theory of Operation.
B2 Secondary Search (Binning) Range
Syntax: B2 ?
The B2 command is a query-only command that returns the value of the frequency range that will be searched
upon a fade acquisition for the secondary (B2) bin.
The value of B2 is determined by the symbol rate and is given in units of kHz. It denotes the frequency range to
search for the carrier outside the B1 range. If the carrier has not been located when all the B2 ranges are
exhausted, the search begins again. A detailed description of the DBR acquisition process can be found in the
chapter on Functional Description and Theory of Operation.
B3 Overall Search (Binning) Range
Syntax: B3 nnnn
B3 ?
The B3 command is used to specify the maximum frequency range that will be searched when the DBR is
attempting to acquire the carrier in either installation or fade acquisition mode. Valid values are between 0 and
4000 in units of kHz offset from the RF frequency plus the acquisition offset defined by AO. The ? parameter
causes the current B3 value to be displayed.
The default values are 3,000 when operating with a DRO LNB and 100 when operating with a PLL LNB.
The nnnn parameter denotes the overall frequency range to search for the carrier. When this value is reached,
the acquisition search is repeated from the beginning. A detailed description of the DBR acquisition process can
be found in the chapter on Functional Description and Theory of Operation.
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