Signals in one-dimensional cellular automata

In this paper, we are interested in signals, from the data can be transmitt ed in a cellular automaton. We study generation of some signals. In this ai m, we investigate a notion of constructibility of increasing functions rela ted to the production of words on the initial cell (in the sense of Fisher for the prime numbers). We establish some closure properties on this class of functions. We also exhibit some impossible moves of data. (C) 1999-Elsev ier Science B.V. All rights reserved.