The preliminary diagnosis of pulmonary diseases in outpatient clinics hinges on the identification of abnormal audible features in breath sounds such as crackles and wheezes by using stethoscope. Representative issues extensively studied on electronic stethoscope are background noise reduction, heart sound enhancement, telecommunication capabilities, and recording features to aid diagnosis.

Numerous new features were studied, and some of them are made commercially available. In fact, the electronic stethoscope is one medical instrument studied recently by many groups of researchers. However, albeit basic, stethoscope is still essential for the diagnoses of many diseases. Significant advances on health care, especially on medical devices, have been made in the past few decades. Clear suppressions were observed in our experiments from both the frequency domain and time domain perspectives. Experiments with the proposed prototype were made using DE2-70 emulation board with recorded body signals obtained from online medical archives. The implementation evaluation with one Altera cyclone IIвЂ“EP2C70F89 shows that the proposed ALE used 45% resources of the chip. We believe that such an implementation is unprecedented and crucial toward a truly useful, standalone medical device in outpatient clinic settings. FPGAs were utilized to implement the ALE functions in hardware to achieve near real-time breath sound processing. The adaptive line enhancer (ALE) was adopted as the filtering methodology to reduce heart sound attributes from the breath sounds obtained via the electronic stethoscope pickup. This paper presents the design and evaluation of the hardware circuit for electronic stethoscopes with heart sound cancellation capabilities using field programmable gate arrays (FPGAs).

Sonic visualiser filter