System for transmission storage and/or multiplexing of information

The method of processing digital information for high density data transmission via an information carrying medium which comprises the steps of translating said information into a series of successive data words each having a given number of binary bits, and successively encoding each of said data words into a format word selected from an alphabet of format words, each having a series of signals equal in number to said given number and having zero average amplitude wherein said series of signals of each said format word contain unique combinations of signals having different discrete values, including additional steps of detecting values of the signals in each of said series upon reception, detecting the format word corresponding to each said detected series on the basis that the combination of said values of said signals in said series is closest to the combination of values of the series of signals which constitute the detected format word, and timing the reception of said format words in accordance with the occurrence of zero amplitude points of the sum of the values of the signals in each of said series.

A system for processing digital information for high density data transmission via an information carrying medium comprising means for translating said information into a series of successive data words each having a given number of binary bits, means for succesively encoding each of said data words into a format word selected from an alphabet of format words, each having a series of signals equal in number to said given number and having zero average amplitude, a source of clock signals, said means for encoding being controlled by said clock signals for producing said format words in coherent relationship therewith, a detector which derives the format words at the receiving end of said medium, said detector including means for identifying the time of reception of each of said format words in accordance with its zero average characteristic, and means responsive to deviation between the time of reception of said format words, as identified by said last named means and the clock signals for controlling the reception of said format words.

The method of synchronously receiving information which is transmitted via an information carrying medium in the form of a series of format words each consisting of a series of signals having a zero average signal level comprising the steps of detecting the points in time when said received words have a zero signal level, and delaying said received words prior to said detecting step to reduce deviations from synchronism from the occurrence of said zero signal level points.

The method of synchronously transmitting and receiving of information comprising the steps of

• encoding said information into a signal constituted of a series of format words each consisting of a series of signals having zero average level for transmission,
• detecting from the received format words a signal occurring each time said received words exhibit a zero level, and
• synchronizing the reception of each of said words with said detected zero level signal.

The method as set forth in claim 13 including the step of transmitting together with said format words a reference tone synchronous with said clock signals and having a frequency which is near the lower end of the frequency spectrum of said format words, comparing said clock signal with said reference tone to provide a second error signal representing deviations in phase therebetween, and delaying said received format words in accordance with said second error signal prior to detection of said zero level signal when said second error signal lies in a relatively low frequency band, while delaying said received format words in response to said error signal named in claim 17 when said last-named error signal lies in a relatively high frequency band above said relatively low band.