A simple high-performance respiratory sound acquisition instrument

Pulmonary auscultation has been one of the most useful clinical procedures to explore the status of patients. However, due to the subjective character of the technique, it is common to find different descriptions of the respiratory sounds. In this work, the development of a respiratory sound acquisition system is described. Such acquisition system is designed according to international standards. Also, a low-power consumption, and low-component count have been taken into consideration. The system is constituted by an air-coupled microphone, an amplifier with a 100 gain, and a stage of analog filtering. The system has a flat frequency response between 105Hz to 2kHz, which is suitable for respiratory sound acquisition. The system was tested in a laboratory and in a physician´s office. The advantages of this system are open architecture, easy implementation, low-power consumption and cost.