This paper deals primarily with the combined experimental and theoretical characterization of a synthetic jet actuator. The experimental approach utilizes a high-frame-rate, digital PIV system, which uses a Photec Phantom V.3.0 CCD camera operating at speeds as high as 1,000 frames per second, and with an image resolution of 512x256 pixels. The resulting digital images are then processed using traditional cross correlation algorithms or newly developed wavelet techniques in order to determine the flowfield quantitatively. The experimental work presented includes measurements and analysis of the flowfield produced by a synthetic jet actuator operating under different frequency and amplitude conditions. The operating conditions selected in this paper were chosen because they generate completely different flowfields. Operation of the actuator with a frequency of 10 Hz and a membrane oscillation amplitude of 75m, produces a flowfield resembling a jet, while operation at 100 Hz with an ampl..