Abstract: A synchronizer for synchronizing a slave tape recorder to a master tape recorder. When the speed of the master recorder exceeds 2.5 times the nominal play speed, the synchronizer causes the slave recorder to lag behind the master recorder by an amount related to the speed of the slave recorder. At lower speeds, the synchronizer causes the slave recorder to lock onto the position and speed of the master recorder. The synchronizer employs time-code readers to read time-code on address tracks on the master and slave recorders. The time-code readers produce not only time-code but also clock pulses which are employed to determine the speed of master and slave with high resolution. Both the time-code readers and a resolver employed in the synchronizer are constructed from gate assemblies rather than processors to reduce execution times for the processor in the synchronizer.