DEVELOPMENT OF A DIGITAL FREQUENCY METER FOR SIGNAL ANALYSIS ON A RESPIRATORY PHYSIOTHERAPY EQUIPMENT
Abstract
This work presents preliminary results of a digital frequency meter that has been designed to measure the frequency of oscillatory vibrations in respiratory physiotherapy devices. Maintain a frequency around 13Hz is important to keep an efficient treatment. Therefore, the proposed circuits and systems are intended to give a visual feedback to the patient with a suggestion of the optimal blow strength. A Linear Hall-Efect Sensor was coupled to the physiotherapy device and the output signal is conditioned through a set of lters. The Fast Fourier Transform of the conditioned signal is used in order to extract frequency domain information to be displayed in real-time to patients.