Implementation of modified delta form for microprocessors using fixed-point arithmetic

This paper considers the finite word length effects of a delta form. A fixed-point implementation of a delta form achieves poor performance due to underflow and overflow in the inverse delta operations. To solve this problem, a new modified delta form is proposed. First, a new integral calculation method named variable modulation method (VMM) is proposed to reduce occurrence of underflow. The principle is based on the methodology of pulse width modulation (PWM). The dynamic range of the calculation is twice or more than the conventional method. Next, the time scales defined as design parameters are introduced to prevent overflow. Then, the implementation procedure based on VMM is described generally. Finally, the simulated results are presented to show the practicality and effectiveness of the proposed algorithm