International Standard Electric Corporation

George A Howells

Douglas E Woodman

Donald Adams Weir

James A Murray

Eric Stanley Usher

Roger M Hochreutiner

A method of balancing digital signals encoded in the Miller Code, which is inherently an unbalanced code. Additional coding rules are utilized based on the use of a transition interval extending from the begining of a bit period to the begining of the next but one bit to define an adjacent pair of Binary I's for certain specific data sequences.

Modified Miller Code encoder

A digital duplex transmission system for use in a local area uses a modified dipulse code from the exchange terminal to the subscriber terminal and either a different modified dipulse code or a modified AMI (Alternate Mark Inversion) code in the other direction to achieve time separation of signals at each terminal. Incorporation of a hybrid separator in each terminal further improves the performance of the system.

Digital duplex transmission system

A time slot interchanging network for use in digital switching. Two shift registers are used, one coupled to receive information from the incoming highway, the other coupled to feed information to the outgoing highway. The shift registers are identical in bit capacity and coupled in parallel. A circulating memory operative at the clock rate of the registers is synchronized with the incoming register to control transfer gates feeding the outgoing register.

Time slot interchanging network

Intelligence is conveyed in a PCM bit stream form with alternate bits being inverted. Additional information is conveyed by violations of the alternate bit rule so that two successive bits have the same polarity. Prior to being coupled to the alternate mark inversion coder a pseudo-random bit stream is mixed by binary addition without carry to the intelligence bit stream to maintain low DC level in the transmitted mixed bit stream and to maintain bit transitions relatively high.

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Bishop's Stortford, United Kingdom

George A Howells