Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Nippon Telegraph and Telephone Corp
Original Assignee
Hitachi Ltd
Nippon Telegraph and Telephone Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd, Nippon Telegraph and Telephone CorpfiledCriticalHitachi Ltd
Priority to JP13630976ApriorityCriticalpatent/JPS5361235A/en
Priority to US05/786,503prioritypatent/US4168534A/en
Publication of JPS5361235ApublicationCriticalpatent/JPS5361235A/en