  We present a novel phase locking scheme for the coherent combination of beam
arrays in the filled aperture configuration. Employing a phase dithering
mechanism for the different beams similar to LOCSET, dithering frequencies for
sequential combination steps are reused. By applying an additional phase
alternating scheme, this allows to use standard synchronized multichannel
lock-in electronics for phase locking a large number of channels even when the
frequency bandwidth of the employed phase actuators is limited.
