AIS Baseband IC with/without RF Synthesiser
CMX7032/CMX7042
$C1 = $0001
$C8 = $0001
$C8 = $0042
; select DSC on Rx1
; reset Rx1
; enable Rx1, Formatted mode
The modem will not report valid data until it has correctly received the initial phasing sequence. Once the
Phasing sequence has been detected, the modem’s internal DPLL bandwidth will be automatically
reduced to improve the error performance. If one of the time-diversity received characters is in error, only
the correct one will be reported. If both characters have errors, the last one received will be reported, with
3
bit 7 (MSB) set. The characters reported back will correspond to the data sequence (see Figure 15) :
A A B1 B2 B3 B4 B5 C D1 D2 D3 D4 D5 E1 E2 F1 F2 F3 G1 G2 G3 H I
Once the H and I fields have been received by the host, the modem will return to searching for the phasing
sequence.
DX/RX
A
B
C
D
E
F
G
H
I
Tele-
command
Message
Format
Specifier
Called Party
Address
Self-
identification
Frequency
Message
Frequency
Message
End of
Sequence
Error-check
Character
Category
Dot
Pattern
Phasing
Sequence
3 identical
DX
characters
1 Rx
2 identical
characters
5 characters
1 character
5 characters 2 characters 3 characters 3 characters
1 character
character
D
X
D
X
D
X
D
X
D
X
D
X
A
A
B
l
B
2
B
3
R
4
B
5
C
D
l
D
2
D
3
D
4
D
5
E
l
E
2
F
l
F
2
F
3
G
l
G
2
G
3
H
I
H
H
Dot pattern
R
X
7
R
X
6
R
X
5
R
X
4
R
X
3
R
X
2
R
X
1
R
X
0
A
A
B
l
B
2
B
3
B
4
B
5
C
D
1
D
2
D
3
D
4
D
5
E
l
E
2
F
l
F
2
F
3
G
l
G
2
G
3
H
I
Figure 15 DSC Format
3
The particular sequence shown here corresponds to the example given in ITU-R M.493-11. Different
Telecommands will produce different sequences of varying lengths.
2012 CML Microsystems Plc
41
D/7032/42_FI1.2/13
CMLMICRO [ CML MICROCIRCUITS ]
