Apogee 2349 DLTM4, Instructions Manual

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AL6300 DATA LINK TEST SET PRODUCT LINE MODEL 2349 DLTM4
A
POGEE
L
ABS
, I
NC
.
21
09.21.2017
210 South 3
rd
Street, North Wales, PA 19454
Tel: 215.699.2060 Fax: 215.699.2061
Table 12: Total Instruction Set
Field Returned Value / Comments Found in
Sub-Menu
PV## The PCM Value field sets the value that is to be set or read into/from the
value defined in the PC## field. Reading or editing a PCM field is a two-
step process. First set the PC## to select which command to read/edit,
then read/set the PV## to read/edit the value. Figure 15
6. APPLICATION NOTES
6.1 GENERALIZED DATA LINK TESTING
CONVOLUTIONAL ENCODER
DAT A
LINK
TEST
SET
TX
VITERBI DECODER
DEMOD/BIT SYNC
RECEIVER
RX
MODULATOR
UP CONVERTER
ANT/PICK OFF
TELEMETRY SYSTEM
OVERVIEW TEST
Figure 19: Typical Telemetry Data Link Block Diagram
The block diagram above illustrates a typical telemetry uplink and receive station loopback test configuration involving
several types of equipment. Testing of these devices can benefit from using more than a simple bit error rate tester. This
note identifies several unique requirements that the AL6300 Data Link Test Set addresses.
6.1.1
“I” & “Q” CHANNELS
Multiple DLTM4 modules may be housed in a single AL6300 DLTS chassis. Two channels are used to test independent
“I” & “Q” channels in a QPSK data link. Operation at the same rate can be achieved by slaving one DLTM4 module
transmitter to the other using the external clock input (ST). Therefore two independent data streams can be generated with
a matched clock phase and frequency. The two channels can alternately be operated at different rates in an unbalanced
QPSK data link.
6.1.2 ERROR SIMULATIONS
The DLTM4 Transmitter provides a number of useful error insertion tools. These errors are inserted after the PRN or
PCM data is generated and before the IRIG bit-code converter.
6.1.2.1 Insert One Error
The first error type is the inversion of a single bit per command. This command provides a quick way to verify that the
DLTM4 receiver, which is showing ZERO errors, is actually connected and properly functioning when it detects and
displays the single error.