A wakefield is generated when electron bunches pass through discontinuities of beam pipes, such as rf cavities. We analyze the relation between the timing jitter of the bunches and the wakefield. From the analysis we derive a mathematical expression through which the jitter as well as the amplitude fluctuation of the bunches can be obtained by measuring the power spectrum of the wake. A measurement of the bunch jitter using this frequency-domain based wakefield analysis is compared with that measured by a time-domain based sampling oscilloscope. The two measurement results correspond well each other. (C) 2000 American Institute of Physics. [S0034-6748(00)03901-0].