Abstract: Method and apparatus by which continuously existing analog voltage command signals for various channels within a control system are changed by determined amounts and senses as a result of supplying "pulse" signals of different durations and polarities. Electronic integrators preferably operating to create linear slope changes in their outputs, and to hold their outputs steady absent any input, are receptive to the change signals ("pulses") of differing durations to create analog command signals which change by increments proportional to the time duration and in a direction corresponding to the polarity of the change signal. This permits computer control of servo devices requiring continuously-existing, changeable command signals in the same fashion as servo devices which respond directly to variable duration, pulse-type change signals.