Stochastic resonance in a chain of threshold elements with unidirectional coupling and spatiotemporal signal

Stochastic resonance is investigated in a chain of unidirectionally coupled threshold elements driven by independent noises and a plane travelling wav e. Both stochastic resonance in an individual element embedded in the chain , characterized by a maximum of the signal-to-noise ratio for nonzero noise intensity, and stochastic resonance with spatiotemporal signal, characteri zed by a maximum of a spatiotemporal input-output correlation function, are observed. Both kinds of stochastic resonance can be enhanced due to proper coupling, although this effect is weaker than for bidirectional coupling a nd occurs for a smaller range of wavelengths of the plane wave. The enhance ment is related to a maximum spatiotemporal synchronization among elements with the same phase of the periodic signal at input.