Nowadays, bone joint disorders are very common in humans. The knee joint abnormality often comes with the increasing age of people. Cartilage degradation and rubbing action of the femoral condyle to the tibial condyle generates the knee joint sounds and this stage turns into osteoarthritis. There are pre-existing diagnosis methods available like X-ray, MRI, etc. but they have their limitations. Some treatment methods are invasive and some are semi-invasive. Early diagnosis of osteoarthritis is possible using vibroarthrography which is a purely non-invasive method and sensor signal output can be featured as an informative tool for next-level treatment. In this study, a contact microphone-based wearable device has been fabricated for knee joint health monitoring and joint angle-based sensor voltage output is characterized. The result of fast Fourier transformation from healthy subjects is observed to be from 0 Hz-100 Hz and short-term Fourier transformation is performed for the obtained decibel value from 40-45 dB. The result of a pathological knee is studied in spectral density analysis and observed a continuous emission of joint sound and signal power distribution is observed over the frequency range of 0 Hz - 500 Hz.