Generation of moiré by nonlinear transfer characteristics

The intermodulation of signal frequencies, or moire, is an effect generally encountered in situations in which periodic or quasi-periodic structures are superimposed. Most familiar are the striking low-frequency patterns achieved by the multiplicative superposition of two structures. In other situations, the intermodulation of signal frequencies may be caused by nonlinear distortions of an input signal. This can be a desired feature in measuring applications or a noise source in transmission or display. Effects of nonlinear transfer characteristics on input signals consisting of more than one frequency are shown. The dependence of resulting moire frequencies on the nonlinearity is evaluated, and common nonlinearities are compared by simulating a moire topography experiment.