A Computer Model of a Magnetic Tape Recorder Servo System

A typical high performance phase-locked capstan speed control system of an analog instrumentation magnetic tape recorder/reproducer is analyzed. Attention is given to component parameter variations, particularly in the dc motor-capstantachometer assembly. A detailed model of the electro-mechanical components of the tape moving system is developed and is adjusted using comparisons of the transfer function calculations and experimental closed loop measurements for a range of parameter values.