Microprocessor controlled D.C. motor for controlling tape feeding means

In a machine including a system for controlling tape feeding means, wherein the system includes means for driving the tape feeding means, an improvement in the system for controlling the tape feeding means, the improvement comprising:

• (a) the driving means including a d.c. motor having an output shaft for driving the tape feeding means;
• (b) means for sensing respective increments of actual angular displacement of the motor output shaft;
• (c) means responsive to the sensing means for counting the respective increments;
• (d) microcomputer means including a microprocessor coupled to the counting means and comprising
• i. clock means for generating successive sampling time periods,
• ii. means for providing first counts respectively representative of successive desired angular displacements of the motor output shaft during successive sampling time periods,
• iii. means for providing second counts respectively representative of actual angular displacements of the motor output shaft during successive sampling time periods, and
• iv. means for compensating for the difference between the first and second counts during each successive sampling time period and generating a pulse width modulated control signal for controlling the d.c. motor, the motor control signal causing the actual angular displacement of the motor output shaft to substantially match the desired angular displacement of the motor output shaft during successive sampling time periods;
• and
• (e) signal amplifying means for operably coupling the motor control signal to the d.c. motor.