Abstract: This digital circuit generates a window during which the data bit transitions of phase encoded data may be read from magnetic tape. This circuit contemplates a system for reading nine track tape and comprises one phase lock loop and window generator for each track, and the logic and control circuitry necessary to deskew and output the data in the form of nine bit bytes. Each phase lock loop is individually free to correct itself to conform to the variations of its own track, and the control circuit can compensate for a total skew of up to four bit times.