Patent ID: 7983326

Claim:
A digital transmission system for transmitting digital video signal of a type wherein a constellation information superimposed video signal of the transmitted digital video signal is mapped to two-dimensional data and transmitted from at least one relay point, said two-dimensional data being identified and reproduced into the constellation information superimposed video signal at a reception side, said system comprising: a display data transmitter provided in said at least one relay point and having first and second memories for alternately writing and reading said two dimensional data to display a transmission status of said transmission signal, said display data transmitter reading out the said two dimensional data alternately from said first and second memories and transmitting said two dimensional data, alternately initializing said first and second memories after reading out; a display data receiver provided in said reception side and having third and fourth memories for receiving said transmitted two dimensional data, writing, reading and outputting said two dimensional data, said display data receiver reading out the two dimensional data alternately from said third and fourth memories and outputting said two dimensional data, alternately initializing said first and second memories after reading out, wherein the transmission status of said at least one relay point is displayed based on the said two dimensional data output from said display data receiver as the constellation information superimposed video signal; and first and second history memories for storing write histories of write locations of said first and second memories respectively, and a decider for deciding only the write locations of said first and second memories on the basis of the write histories of the first and second write memories and outputting said two dimensional data for expressing transmission status display information about the write locations, wherein said two dimensional data expressing transmission status display information is read out from each of said third and fourth memories in units of one of one-dimensional divisions of addresses of said each of said third and fourth memories.