Abstract: An addressing device for a memory, such as a dynamic memory ROM or RAM, addressable by address words at a predetermined clock-period rate. Each address word is made up of first and second address words composed of least significant and most significant bits of the address word respectively. The first and second address words are multiplexed. The device comprises an adding circuit for incrementing the first address words in terms of a predetermined digital signal carrying words that are synchronous with the first address words and for incrementing the second address word in each address word by unity whenever the first word of the address word has bits all equal to "1", and a shift circuit looped across the adding circuit in order to deliver the first and second multiplexed address words to the memory.

Abstract: This invention relates to digital transmission techniques whereby information produced in asynchronous form, for instance by variable-length coding and/or by conditional coding, is intended for transmission through a synchronous digital transmission path. More particularly, the invention concerns a receiving device comprising a picture buffer memory having a content that can be different from that of a picture buffer memory included in a transmitting device of the system, a circuit for detecting picture line and field synchronizations, a circuit for transcoding video information prior to its writing in the receiving device buffer memory and a circuit for monitoring writing and reading addresses in the buffer memory in terms of the detected synchronizations. A partial decoding of the video information is performed prior to entry in the receiving device buffer memory, and a synchronization of this memory is independent of the content in the transmitting device buffer memory.

Abstract: A conditional replenishment video data transmission system involves the transmission of updating digital data for clusters of consecutive picture elements, all or most of which show a change since the previous frame, in lines of a raster over an image to be transmitted. The lines of the raster are numbered cyclically in groups of 8, the numbers being part of line synchronizing code words, and the position along a line of the first element of each cluster is identified by a number. The data are transmitted at a constant rate from a transmitter buffer to a receiver buffer and an auxiliary data store records the addresses of the line synchronizing code words in the receiver buffer. The address of the receiver buffer read by a reading means can be corrected by reference to the address data in the auxiliary storage means if for example the line numbers do not follow in sequence or the element addresses are not in ascending order due to corruption during transmission.