A New Real Differentiator with Low-Pass Filter in Control Loop

The paper offers a new real differentiator realized as a closed loop system with a low-pass filter (LPF) within the control loop. The cascade of the LPF, with a considerable time constant, and an integrator is treated as the controlled object. The controller is of derivative (D) type with a limiter and a high gain. The closed loop time constant of the obtained real differentiator is small. The limiter and the LPF significantly attenuate noises. Simulation comparison between the proposed differentiator and the known differentiators reveals certain advantages of the proposed solution under appropriate conditions.