AIS Baseband IC with/without RF Synthesiser
CMX7032/CMX7042
1
Brief Description
The highly integrated Baseband Signalling Processor ICs CMX7032 and CMX7042 fulfil the requirements
of the Class B Marine Automatic Identification System (AIS) transponder market. The CMX7042 is
identical in functionality to the CMX7032 with the exception that the two on-chip RF Synthesisers have
been deleted, which enables it to be supplied in a smaller package. This document refers to both parts
generically as the CMX7032/CMX7042, unless otherwise stated.
The AIS system allows ships and base stations to communicate their position and other data to each other
without the need for a centralised controller. This allows vessels to “see” each other and take appropriate
action to avoid collision and so improve marine safety. The system uses a GMSK 9600 baud data link in
the Marine VHF radio band. The system requirements are defined in ITU-R M.1371-4.
The CMX7032/CMX7042 devices utilise CML’s proprietary FirmASIC component technology. On-chip
sub-systems are configured by a Function Image™: this is a data file that is uploaded during device
initialization which defines the device's function and feature set. The Function Image™ can be loaded
automatically from an external serial memory or from a host µController over the built-in C-BUS serial
interface. The device's functions and features can be enhanced by subsequent Function Image™
releases, facilitating in-the-field upgrades.
The CMX7032/CMX7042, when used with 7032/7042FI-1.x, is half duplex in operation, comprising two
parallel Limiter-Discriminator Rx paths and one I/Q or two-point modulation Tx path. The Rx paths are
configurable for AIS or DSC operation, the Tx for AIS only. The device performs signal
modulation/demodulation with associated AIS functions, such as training sequence detection, NRZI
conversion and HDLC processing (flags, bit stuffing/de-stuffing, CRC generate/check). Integrated Rx/Tx
data buffers are also provided. This greatly reduces the processing requirements of the host µC. Provision
of a number of auxiliary ADCs and DACs further simplifies the system hardware design, reducing the
overall equipment cost and size. This document refers specifically to the features provided by the
CMX7032/CMX7042 Function Image™ FI-1.2.
This Datasheet is the first part of a two-part document comprising Datasheet and User Manual: the User
Manual can be obtained by registering your interest in this product with your local CML representative.
2012 CML Microsystems Plc
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D/7032/42_FI1.2/13
CMLMICRO [ CML MICROCIRCUITS ]
