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Subject: DE70321 AIS Demo Board Evaluation (Enhancement A)
This document contains typical system level test results for the DE70321 AIS
Demonstration Kit, an evaluation and demonstration resource that contains an AIS
demonstration transmitter and dual receiver along with a CMX7032 AIS Baseband Processor.
[application note link].
Subject: DE70321 AIS Demo Board Evaluation (Enhancement B)
This document contains details of how the performance of designs based on the DE70321 AIS
Demonstration Kit may be enhanced for certain applications.
For full class B compliance, the receivers’ local oscillators are controlled using an LMX2332
dual PLL IC. In particular, the 1st LOs require excellent phase noise performance in order to
meet the demanding adjacent channel rejection standard.
Whilst the existing design achieves this at the AIS operating frequencies, improvements can be
made to the VCO circuits to give better ACR performance (typically 72-76dB rejection) across the
entire marine band.
[application note link].
Subject: DE70321 AIS Demo Board Evaluation (Enhancement C)
Details of how the performance of designs based on the DE70321 AIS Demonstration Kit may be further enhanced by dc coupling the IF demodulator IC audio outputs to the CMX7032 inputs. At present these are low-frequency ac coupled.
A further modification to the VCTCXO control line may also provide improvements in receive only
applications.
The changes have been found to improve the performance of the receiver in certain circumstances
and in some cases with discontinuous AIS bursts the improvement is significant.
It is recommended that all users of the DE70321 with units of ‘mod state’ 3 or earlier implement
these changes.
[application note link].