IRIG 106-99  CHAPTER 9 - TELEMETRY ATTRIBUTES TRANSFER STANDARD, Continued....
Start of Chapter 9
9.5.2 General Information (G)
9.5.3 Transmission Attributes (T)
9.5.4 Tape Source Attributes (R)
9.5.6.1 PCM Format Attributes (P)
9.5.6.2 PCM Measurement Description (D)
9.5.6.3 1553 Bus Data Attributes (B)
9.5.7 PAM Attributes (A)
9.5.8 Data Conversion Attributes (C)
9.5.9 Airborne Hardware Attributes (H)
CHAPTER 9

TELEMETRY ATTRIBUTES TRANSFER STANDARD, Continued....

9.5.5 Multiplex/Modulation Attributes (M)



9.5.5 Multiplex/Modulation Attributes (M). The composite baseband waveform is received from the receiver or tape reproducer electronics and is passed to the demultiplexer/demodulator for further processing. Figure 9-5 summarizes the information that is required to continue processing the data. The composite baseband waveform may consist of any number of signals, which are modulated directly onto the RF carrier including a baseband data signal, and one or more subcarriers.

The baseband data signal may be PCM, pulse amplitude modulation (PAM), or analog data. The PCM and PAM data streams must be defined in terms of a data link name. This data link name is unique for each system that contains different data, has a different format, or has a different data rate. The analog measurand is typically converted into engineering units appropriate for the measurand. The measurement name provides the connection to the Data Conversion Attributes Group (C).

Subcarriers, both standard and nonstandard, may be part of the baseband composite waveform. These, in turn, may be modulated with PCM, PAM, or analog data. As with the baseband data signal, these data channels must be defined. Table 9-4 specifies the required information for the data signal attributes.


Multiplex/Modulation Attributes Group (M).
Figure 9-5.  Multiplex/Modulation Attributes Group (M).



TABLE 9-4. MULTIPLEX/MODULATION GROUP (M)

R
O
W


PARAMETER

MAX
FIELD
SIZE


CODE
NAME


DEFINITION

1

DATA SOURCE ID

32

M-x\ID

DATA SOURCE IDENTIFICATION.

COMPOSITE SIGNAL STRUCTURE

2

SIGNAL STRUCTURE TYPE

7

M-x\BB1

SPECIFY THE COMPOSITE BASEBAND SIGNAL STRUCTURE:
PCM  HYBRID: ANA/SCO
PAM  PAM/SCO
ANALOG  PCM/SCO
SCO's  OTHER.

3

MODULATION SENSE

3

M-x\BB2

SPECIFY THE MODULATION SENSE:
‘ POS’ - INDICATES THAT AN INCREASING VOLTAGE RESULTS IN AN INCREASE IN FREQUENCY.
‘NEG’ - INDICATES THAT A DECREASING VOLTAGE RESULTS IN AN INCREASE IN FREQUENCY.

4

COMPOSITE LPF BANDWIDTH

6

M-x\BB3

GIVE THE LOW PASS BANDWIDTH OF THE COMPOSITE WAVEFORM, IN kHz.(3 dB CUT-OFF FREQUENCY)

BASEBAND SIGNAL

5

BASEBAND SIGNAL TYPE

3

M-x\BSG1

TYPE OF BASEBAND DATA: ‘PCM’ ‘ANA’(ANALOG)
‘PAM’ ‘OTH’(OTHER) ‘NON’(NONE).

LOW PASS FILTER

6

BANDWIDTH

6

M-x\BSF1

SPECIFY LOW PASS FILTER BANDWIDTH,3dB, CUT OFF FREQUENCY, IN kHz.

7

TYPE

2

M-x\BSF2

SPECIFY THE FILTER TYPE:
CONSTANT AMPLITUDE – ‘CA’
CONSTANT DELAY – ‘CD’
OTHER - ‘OT’, DEFINE IN THE
    COMMENT RECORD.

BASEBAND DATA LINK TYPE

PCM OR PAM

8

DATA LINK NAME

32

M-x\BB\DLN

SPECIFY THE DATA LINK NAME FOR PCM OR PAM DATA FORMAT.

ANALOG

9

MEASUREMENT NAME

32

M-x\BB\MN

GIVE THE MEASURAND NAME.

SUBCARRIERS

10

NUMBER OF SUBCARRIERS

2

M-x\SCO\N

SPECIFY THE NUMBER OF SUBCARRIERS ON THIS DATA LINK.

IRIG SUBCARRIERS

11

NUMBER OF SCOs

2

M-x\SI\N

SPECIFY THE NUMBER OF IRIG SUBCARRIERS.

12

SCO NUMBER

5

M-x\SI1-n

GIVE THE IRIG CHANNEL NUMBER FOR THE SUBCARRIER.

13

SCO #n DATA TYPE

3

M-x\SI2-n

SPECIFY THE TYPE OF DATA ON THE SUBCARRIER:
   PCM – ‘PCM’    ANALOG – ‘ANA’
  PAM – ‘PAM'    OTHER – ‘OTH’.

14

MODULATION SENSE

3

M-x\SI3-n

SPECIFY THE MODULATION SENSE:
‘POS’ - INDICATES THAT AN INCREASING VOLTAGE RESULTS IN AN INCREASE IN FREQUENCY.
‘NEG’ - INDICATES THAT A DECREASING VOLTAGE RESULTS IN AN INCREASE IN FREQUENCY.

LOW PASS FILTER

15

BANDWIDTH

6

M-x\SIF1-n

SPECIFY THE LOW PASS FILTER CUT-OFF FREQUENCY (3dB), IN kHz.

16

TYPE

2

M-x\SIF2-n

SPECIFY THE FILTER TYPE:
CONSTANT AMPLITUDE – ‘CA’
CONSTANT DELAY – ‘CD’
OTHER – ‘OT’, DEFINE IN THE
    COMMENT RECORD.

DATA LINK TYPE

PCM OR PAM

17

DATA LINK NAME

32

M-x\SI\
DLN-n

SPECIFY THE DATA LINK NAME FOR PCM AND PAM DATA FORMATS.

ANALOG

18

MEASUREMENT NAME

32

M-x\SI\
MN-n

GIVE THE MEASURAND NAME.

REPEAT THE ABOVE FOR EACH IRIG SUBCARRIER ON THIS CARRIER.

19

OTHER

1

M-x\SO

ARE THERE NONSTANDARD SUBCARRIERS?   YES – ‘Y’,    NO – ‘N’.
DEFINE IN THE COMMENTS.

20

REFERENCE CHANNEL

6

M-x\RC

FREQUENCY OF REFERENCE CHANNEL IN kHz, IF APPLICABLE.

COMMENTS

21

COMMENTS

3200

M-x\COM

PROVIDE THE ADDITIONAL INFORMATION REQUIRED AND ANY OTHER INFORMATION DESIRED.



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