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:
Mar. 15, 1977
Filed:
Feb. 09, 1976
Neil H Jagoda, Framingham, MA (US);
Klaus Kubierschky, North Reading, MA (US);
Adrian G Roy, Jr, Kingston, MA (US);
American Science & Engineering, Inc., Cambridge, MA (US);
Abstract
A remote meter-reading system interrogates meter stations over power lines and receives encoded meter readings over the power lines in synchronism with the power line frequency by superimposing a digitally modulated signal over the 60-Hz power frequency. The central control station transmits at a data rate of 60-baud and receives at a data rate that is 60-baud or a submultiple thereof, to reduce the demands on the remote meter station transceiver as compared to those on the central control unit transceiver. The bit clock at the central control unit and the meter stations is derived from the 60-Hz power line phase available at each station. Each meter station achieves message synchronization by continuously monitoring the data bit stream for a preset synchronization code and thereafter treats the following 21 data bits as address and function codes. Each meter station that is addressed responds at the data rate designated by the function code by transmitting with a message including the address and function bits for comparison at the central control station with that originally sent to facilitate error detection, and the meter reading encoded according to an error detecting code. A binary data bit is represented by quadrature phase lead and lag relative to reference phase of the character.