Pulse width modulation technique

摘要

Improved pulse width modulation technique provides for an increased sampling rate without an increased ON/OFF rate at associated control devices. Both ON/OFF and OFF/ON edges in a PWM signal are modulated. The system then samples at twice the pulse turn-on rate to provide more frequent sampling. System response time may be decreased without an increase in the operating frequency for the associated control device. Particular application of the present invention may be found in continuously variable transmission systems which utilize PWM-controlled electrohydraulic valves for ratio control, line pressure control and clutch control. A system for implementing the PWM signal has a duty-cycle calculator coupled with timing circuits to control input data reading functions and circuit enabling, leading edge and trailing edge regulators and an output pulse generator.