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:
Jan. 26, 1993
Filed:
Dec. 26, 1990
Melvin G Montgomery, Plano, TX (US);
Atlantic Richfield Company, Los Angeles, CA (US);
Abstract
A phase shift keyed telemetry system is disclosed, which is particularly adapted to demodulation of phase shift keyed signals where the medium of transmission is non-ideal, such that transitional cycles are present at each change of phase of the transmitted data. Demodulation is accomplished by comparison of the input signal to a reference signal generated from the input signal itself. The reference signal is generated by frequency dividing the input signal, preferably after full wave rectifying, by a multiple which is larger than the number of transitional cycles expected; the frequency divided signal is then multiplied in frequency to substantially match the frequency of the input signal. The use of the divider and multiplier removes the effects of transitional cycles of varying phase in generating the reference signal. A phase locked loop in the reference signal generating circuit also reduces the effects of frequency and phase shifting during the transitional cycles, as well as providing tolerance for missing cycles due to system noise.