Compensation of Reconstruction Filter Effect in Digital Signal Processing System

This paper proposes the reduction effect of reconstruction filter for digital signal processing system. It is well known that the reconstruction filter limits the bandwidth of output signal processing and the output signal is staircase form or has high frequency components. For effect reduction we use the nonrecursive system which corresponds with the inverse system function of the reconstruction filter. The initial step starts with the analog system function of the reconstruction filter and is converted to a discrete-time system using the approximation of derivative technique and inverse system. This inverse discrete-time system function is a nonrecursive system to compensate the reduction effect of the reconstruction filter implemented by using the software. For hardware experiments, we use TMS320C31 digital signal processor, D/A, PIC-32 microcontroller, PWM analog output. The experimental results of the proposed principle show that it can be used to compensate the bandwidth and reduce the total harmonic distortion (THD) of high frequency signal. In addition, this experiment shows that the nonrecursive system for compensation uses only first-order system and it does not utilizes any more processor. Furthermore, it is able to increase the performance. The applications are such as digital filtering, digital control and audio processing. They can be done with high accuracy using the proposed principle.