A Low-Cost PC-Based Virtual Oscilloscope

The integration of personal computers (PCs) with the present-day measurement and instrumentation world has opened up the door for “virtual instrumentation.” This paper describes the development of a low-cost, PC-based, virtual digital oscilloscope. A data acquisition device using the computer parallel port has been fabricated with full analog interface and 8-b analog-to-digital converter with associated control-logic and timing circuitries. A software package aimed at managing the acquisition process and displaying the acquired signal has also been developed. This device has been conceived as a simple plug-in board to be incorporated to any IBM PC parallel port—thus, in many cases, eliminating the requirements of multiple, expensive, digital oscilloscopes. The project, initially designed as an undergraduate thesis, is currently being used for laboratory instructional purposes. The features of this device make it suitable for implementing as an educational resource for undergraduate students from Electrical, Electronics, Instrumentation, and Computer Science faculties.