Means of Digital Processing and Generation of Sound and Ultrasound Frequency Signals in Teaching and Research Work

Abstract

The authors analyse the most common free and shareware software for analysis and generation of sound signals, which is based on the use of ADC (analogue-to-digital converter) and DAC (digital-to-analogue converter) of a computer sound card. With the accordance to the present paper, there is practically no domestic Ukrainian-language software for working with ADC and DAC sound cards. The authors propose to use affordable personal mobile cardiographs, both for the study of biopotentials and the processing of other low-frequency signals. The staff of Chemistry Department of G.S. Skovoroda KhNPU has been developing a software and methodological complex of SchoolKit, one of the applications of which is called SoundCardScientificKit. It includes an audio signal analyzer, a special shape signal generator, and a frequency spectrometer. This software is universal and widely used. Therefore, it can be used both in research, and to demonstrate physical phenomena associated with sound or electrical oscillations of low frequency from 20 to 20,000 Hz. The main functions and interface of the SoundCardScientificKit software are described. The authors conducted testing the special form signal generator of the SoundCardScientificKit application with Realteck High Definition Audio sound card. The results showed the reproduction of the programmed frequency to be occuring with high accuracy. The principle circuits of potential amplifiers used in the development of electrocardiographs, myographs, etc., were analyzed. A simple circuit of the biopotential amplifier based on three TL082 chips has been developed, which includes a high-efficiency noise filter with a frequency of 50 Hz. The paper shows this amplifier to have been used to obtain an ECG (electrocardiogram). Particular attention is paid to the environmental aspects of the creative activity of students. The authors suggest that, when developing electronic devices, if possible, one can use the equipment that requires disposal. Reusing unusable equipment not only removes the problems associated with processing, but also allows students to learn about the principles of operation and design features.