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:
Jun. 30, 1981
Filed:
Aug. 03, 1979
Hirotoshi Shirasu, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A signal processing apparatus for subscriber circuits is disclosed which comprises a plurality of circuits each for extracting a signal corresponding to a.c. and d.c. signals flowing through each of a plurality of subscriber circuits, an analog multiplexing circuit connected to the output terminal of each of the plurality of extracting circuits, an analog-to-digital converter connected to the output terminal of the analog multiplexing circuit, and a signal processing circuit connected to the output terminal of the analog-to-digital converter and receiving successively and periodically a digital signal corresponding to the output signal of each of the extracting circuits for processing the digital signal to detect the state of each of the subscriber circuits, the reception of the digital signal being made by sending a selective signal to the analog multiplexing circuit.