  The usual interpretation of noise is represented by a sum of many independent
two-level elementary random signals with a distribution of relaxation times. In
this paper it is demonstrated that also the superposition of many similar
single-sided two-level signals, with the same relaxation time, produces noise.
This is possible tanks to the coincidences among the signals which introduce
cross-correlations and tune locally the resulting process in trains of
pseudo-periodic pulses. Computer simulations demonstrate the reliability of
this model, which permits to insert in an coherent framework other models
solving problems still open.
