Clock Variation Impact on Digital Control System Performance

Digital controls have become the primary form of control in numerous applications due to the advancements in semiconductor industry and lower cost. Digital control algorithms implemented on digital signal processors (DSPs) or microcontrollers execute the algorithm at a specified clock frequency. Discrete time algorithms such as digital filters and digital PID controllers require the sampling period in the controller design, which is directly related to the microcontroller clock frequency. Due to aging, manufacturing process defects and environment conditions cause the clock frequency to drift from the specification. Such variation affects the discrete time algorithm performance deviate from expected performance.