We present a description of a phased array system using the far-field point spread function to estimate the tilt and piston errors. Digital control electronics were utilized to phase one beam to two others that were already in phase to simulate a multiple-aperture telescope system. A control algorithm for estimation of tilt and piston errors similar to the Newton-Raphson algorithm for locating the roots of a function was implemented. A simulation of the system was performed, the system hardware was built, and the system was tested in both an off-line software test and an experimental test-bed. Piston phasing with a capture range of X/4 and closed-loop tilt phasing with a bandwidth of 2 Hz were accomplished.