Genesys GDR- COM Series, Installation Manual, Page: 56 / 62

GDR-XXXX NAV/COMM INSTALLATION MANUAL
64-000109 Page 56 of 62
33. ARINC Label 173, LOC Deviation
The calculated ddm of the Localizer is transmitted on ARINC label 173. When valid data is not
present, the SSM is set to “No Computed Data”.
Table 28: LOC Deviation Specification, ARINC Label 173
Label PARAMETER
NAME
UNITS RANGE SIG.
BITS
APPROX.
RESOLUTION
173 Localizer Deviation DDM ± 0.4 12 0.0001
Table 29: LOC Deviation Format, ARINC Label 173
P
a
ri
ty
(
o
d
d
)
S
ig
n
/S
ta
tus
Ma
tri
x
DATA FIELD
MSB LSB
Res
(SDI)
LOC Deviation
Octal
LSB MSB
1 2 4 1 2 4 1 2
Bit # 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
+0.021 DDM 1 1 1 0 0 0 0 0 1 1 0 1 1 0 0 0 P P P P P P 0 0 1 1 0 1 1 1 1 0
3 7 1
Note: 1) “P” denotes a pad with a “0” value.
2) Negative values are encoded as the two’s complements of positive values and the
negative sign is annunciated in bit 29.
3) The transmitted binary value is found as (ddm)/0.4 * 4096, encoded as two’s
complement.
4) The two's complement of an N-bit number is the result of subtracting the number
from 2
N
.
Table 30: Status Matrix definition
Bit 31 Bit 30 Status
0 0 Failure Warning
0 1 No Computed Data
1 0 Functional Test
1 1 Functional
Table 31: Sign Bit definition
Bit 29 Meaning
0 Right
1 Left