Abstract: The slaved ramp voltage generator disclosed herein facilitates the writing of characters by a servo controlled stylus carried on a moving carriage. The carriage is driven at a selectable speed and the drive system generates pulse signals at a rate which is proportional to carriage speed. A digital counter is advanced by these pulse signals and the digital value held by the counter is converted to an analog voltage which varies in proportion to displacement of the carriage. This carriage displacement voltage is summed with a vector-defining position voltage to obtain a control voltage which drives the stylus servo mechanism to effect writing with respect to a moving frame of reference.