Design and Development of Resistor Capacitor (RC) Bode Plot for Filters

Abstract

The aim of this work is to design and develop a Resistor Capacitor (RC) bode plotting and system for use in the laboratory on which several circuits and filters of different topologies can be analyzed and tested after construction.The maximum measuring frequency for this work will be limited to Audio frequencies, since common op-amps use analogue circuit design and have a maximum unity gain bandwidth of 1MZ. In this design, we were able to analyse systems whose operating frequencies are limited to less than 22KHz. This involve the generation of an electrically tunable sine wave generator whose frequency can be automatically tuned by the computer. Sine waves was used due to low harmonic content, this ensures that the Figureures which we obtained have minimal distortions as expected from an ideal sine wave source. The system was based on 8-bit microcontroller, which generally gives a low resolution output. In order to improve the systems resolution, we  used  relatively low reference voltages. The 8052 micro-controller can operate at a maximum frequency of 33 MHz, by operating at this maximum available frequency, we were able to improve  our system processing speed, thus ensuring that measurements and readings are obtained in almost real time. . The system graphical user interface was developed with the VISUAL BASIC.NET program and will run on Microsoft operating system.

On completion of the work, the design and developed device provides actual frequency response as compared to the ideal response  provided by a software based Bode Plotter for a passive filter.