In practice

nonuniform sampling occurs in high speed data acquisition system due to imperfect sampling timebase. In this paper

we first present a mode of nonuniformly sampled signals and basic principle of digital spectrum analysis

and then derive in detail digital spectra representation of nonuniformly sampled periodic signal. Some important properties are explored. Finally

four special but interesting sampling cases are discussed and the signal-to-noise ratio

S/N

is derived in closed form. Several significant conclusions are drawn. The thought and conclusion in this paper are useful for analysing nonuniform time sequence

investigating spectrum estimation and designing high speed data acquisition system.