On a conjecture on time-warped band-limited signals

J.J. Clark conjectured (see Proc. SPIE Inst. Soc. Opt. Eng., vol.1199, pt.3, p.1156-62, 1989) that, when a bandlimited signal f is time warped by composition with a monotone function gamma , a certain signal derived from gamma is also bandlimited if and only if gamma is affine. This correspondence shows that for a large class of gamma the conjecture is true. >