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:
Aug. 31, 1976
Filed:
Feb. 01, 1974
Takehiko Yoshino, Yokohama, JA;
Katsuo Mohri, Yokohama, JA;
Nippon Hoso Kyokai, Tokyo, JA;
Hitachi, Ltd., Tokyo, JA;
Abstract
A multi-level code transmission system for restoring the d.c. component of a received signal by peak-clamping of the peak of the received synchronizing signal to a fixed level so as to establish the synchronization of a receiving end prior to an establishment of synchronization at the receiving end and for effecting pulse-clamping of the reference level of a following received signal after the establishment of synchronization at the timing of a clamping pulse relating to the synchronizing signal. In the case of transmitting a multi-level code signal such as an audio PCM signal together with an analogue signal such as a picture signal alternately, for example in a still picture transmission system, the d.c. level of the received signal is varied due to the low cutoff frequency characteristic of the transmission line, the result of which is the occurrence of a code error in a reproduced code signal at the receiving end. In order to obviate such a code error, the present invention uses two kinds of clamping, i.e., peak-clamping and pulse-clamping before and after the establishment of synchronization at the receiving end, respectively. According to this invention, the multi-level code signal can be reproduced with high fidelity.