Drake SCT2x4 BBT Transcoder - Manual (Page 9)

9 Setup and Programming (continued)
this section provides additional details regarding the selectable items shown in the ‘adjust’ mode on the
Software flow Chart on page 8.
SETUP: INPUTS
UNIT ID: Select the desired unit identification number when connecting the 'RS232 iN' connector to a PC or
modem for remote control using 'Drake Remote Control Software'. Numbers 1 thru 63 may be used. if zero (0)
is selected, the PC will ignore the unit.
RS232 BAUD RATE: this setting determines the baud rate at which the SCt2x4 communicates with the
remote PC. Settings available are 2400, 4800, 9600 and 19,200. All units 'daisy chained' to the remote PC or
modem must be set to the same baud rate.
SAT 1 and SAT 2: these menu items provide means for selecting the desired preprogrammed satellite and
transponder on the SAt 1 and SAt 2 inputs. each selection automatically programs the correct transponder
frequency as well as mode and symrate into the SCt2x4.
SAT 1 and SAT 2 LNB: the SCt2x4 receives its input signal from the if outputs of two independent LNBs
connected to the SAt1 and SAt 2 inputs. each of these inputs is capable or providing power to the LNB.
However, in some situations where an LNB output is split among several other devices, it may be undesirable
for the SCt2x4 to provide LNB power. these menu entries provide the means of turning off LNB power to one
or both SAt inputs for these situations.
SETUP: QAM 1,2,3 & 4
QAM MODE: this menu allows the user to set the modulation type for the output. Choices range from qAm-
16A through qAm-1024B. 'A' suffixes indicate DvB compliant feC and the B suffixes indicate DigiCipher
ii feC encoding. Note that the output qAm mode usually must be qAm-256. for CAtv systems using
DigiCipher ii, select the qAm-256B mode. for DiSH Network qAm distribution or other DvB systems using
DvB set tops, choose the qAm-256A mode. GRAy eNCoDiNG: this menu is only available when qAm
modes qAm-16A through qAm-1024A, are selected. the choices are DvB and DAviC. Gray encoding is
normally not used for video data.
QAM SYMRATE: Preset or manual: if PReSet is selected, the symbol rate will be automatically set to the
‘normal’ rate based on the qAm mode that is selected and assuming a 6 mHz wide qAm channel. if mANUAL
is selected, pressing the right or left arrow buttons will allow selection of symrates from 1.000 thru 7.000
mSym/Sec.
QAM SYMRATE: this menu item only appears of ‘manual’ is selected in the previously described menu item.
it allows selection of the output qAm baudrate or symbol rate. Set as required by the set top box.
INTERLEAVER: this menu item only appears if qAm-64B, qAm-256B, or qAm-1024B is selected and
provides the means to set the qAm modulator interleaver. Choose among the available selections based upon
your system / set top box requirements. for typical 256-qAm DigiCipher ii CAtv systems, i128, J1 is the most
commonly used interleave setting but many other choices are available. this menu does not appear in the
adjust mode if the qAm mode is A (DvB) as there is only one choice in the DvB standard.
OUTPUT FORMAT: for normal operation, select NoRmAL. for system level set up, choose Cw to provide
a Cw carrier at the center frequency of the output channel for use in leveling a system when a qAm power
meter is not available. to disable all Rf output, select StANDBy. in the Cw mode, the Cw carrier can be
measured on a spectrum analyzer without a need to apply a bandwidth correction or it can be measured with
an analog meter tuned to channel center. the Cw power measured will equal the channel qAm power when
the modulator is returned to NoRmAL output mode. Usually qAm signals are set 5 dB to 10 dB below analog
NtSC channels when balancing a system.
PRBS menu entries are used for testing purposes only and should normally not be selected by the user.
OUTPUT CHANMAP, OUTPUT CHANNEL: Select the desired eiA CAtv channel output using these two
menus.
RF LEVEL: Select the desired Rf output signal level. the available range is between +45 dBmv and +56
dBmv, selectable in 0.5 dB steps. the output accuracy is ± 1 dB.