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Acquisition signal transmitterAn encoded information transmitter which transmits a radio frequency carrier that is amplitude modulated by a constant frequency waveform and thereafter amplitude modulated by a predetermined encoded waveform, the constant frequency waveform modulated carrier constituting an acquisition signal and the encoded waveform modulated carrier constituting an information bearing signal, the acquisition signal providing enhanced signal acquisition and interference rejection favoring the information bearing signal. One specific application for this transmitter is as a distress transmitter where a conventional, legislated audio tone modulated signal is transmitted followed first by the acquisition signal and then the information bearing signal, the information bearing signal being encoded with, among other things, vehicle identification data. The acquistion signal enables a receiver to acquire the information bearing signal where the received signal is low and/or where the received signal has a low signal-to-noise ratio in an environment where there are multiple signals in the same frequency band as the information bearing signal.
Document ID
20080008809
Acquisition Source
Headquarters
Document Type
Other - Patent
Authors
Friedman, Morton L.
Date Acquired
August 24, 2013
Publication Date
December 19, 1989
Subject Category
Communications And Radar
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Patent
US-Patent-4,888,595
Patent Application
US-Patent-Appl-SN-165355

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