The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 09, 1993
Filed:
Jul. 23, 1990
Harold R Walker, Edison, NJ (US);
Other;
Abstract
An improved binary data communication system employs an improved VPSK encoding procedure wherein each input data bit has a bit period of M clock periods, and the data bit polarity changes are phase shift key coded with waveform widths of M/M, M+1/M, and M+2/M bit periods wherein M is an even integer greater than 3. Each of the data bits (except the last one in an encoding cycle) is encoded in an encoding signal which switches back and forth between '1' and '0' polarities and has assigned widths representing whether or not the polarity of the data bit is changed from that of the previous data bit, and whether it is the last (M-1th) polarity change in the encoding cycle. At the receiving end, a complementary procedure is used to decode the encoded signal. For transmission, the encoded signal is filtered for higher order harmonics and integrated in order to provide a sine wave output shifted 90 degrees in phase. Upon reception, the received signal is differentiated and a zero crossover detector is used to regenerate the encoded signal for decoding. The improved encoding technique can achieve Nyquist efficiencies of 10, 12.6, and 15.3 bits/Hz-bandwidth, or higher, for M equal to 6, 8, and 10 modulation levels, respectively. The encoded signal spectrum fits typically within about 1/6 of the bandwidth of the baseband NRZ signal. The encoded signal is particularly useful for transmission at high data rates in telephone, RF modulated carriers, and other transmission systems.