The book discusses digital regulators and high-precision rotation speed meters. Errors of analog regulators and speed meters are briefly analyzed. Circuit solutions of the main units of digital regulators and speed meters are given. Formulas are derived for selection of main parameters of regulators and speed meters by specified accuracy. Practical digital rotation speed measurement and control systems are contemplated, particularly for metallurgical applications. The material of the book is designed for engineers and technicians involved in the field of electric drive automation.