Accession Number : ADD017518
Title : Communications System Using a Sharply Bandlimited Keying Waveform.
Descriptive Note : Patent Application, Filed 31 Mar 95,
Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC
Personal Author(s) : Waters, William M
PDF Url : ADD017518
Report Date : 31 Mar 1995
Pagination or Media Count : 31
Abstract : It is the object of this invention to transform a communications sequence in a communications system into an analog signal which is spectrally confined to the band available for the transmission within a band limited communications channel without compromising communication accuracy. Another object of this invention is to improve spectral confinement thereby allowing closer channel spacing and better electromagnetic compatibility among radar, navigation, and communications systems. These and other objects are achieved by a communication system using sharply bandlimited signals for sampled data communications wherein a sharply bandlimited waveform is computed for each sample value in a sequence of data samples. Each waveform is centered at a sample point, is weighted by the corresponding data value, and is truncated outside an appropriate time interval. Resulting data-weighted waveforms are summed in the computer for all data samples of the sequence to be communicated, and the result is converted to analog form, up-converted to the desired carrier frequency, and transmitted. Because the signal spectrum is sharply bandlimited, communication channels may be spaced more closely, permitting more channels in the same frequency band.
Descriptors : *PATENT APPLICATIONS, *DATA TRANSMISSION SYSTEMS, *WAVEFORMS, *COMMUNICATION AND RADIO SYSTEMS, *ANALOG SIGNALS, CONVERSION, SIGNAL PROCESSING, DATA PROCESSING, TIME INTERVALS, ACCURACY, ELECTROMAGNETIC WAVE PROPAGATION, RADAR, SEQUENCES, FREQUENCY BANDS, SPECTRA, NAVIGATION, LIMITATIONS, SIGNALS, SAMPLING, CONFINEMENT(GENERAL), BANDWIDTH, CHANNELS, ELECTROMAGNETIC COMPATIBILITY, CARRIER FREQUENCIES
Subject Categories : Radio Communications
Distribution Statement : APPROVED FOR PUBLIC RELEASE