An RF Stethoscope with Digital SSB Frequency Modulation for Use in a Noisy Environment

A 24 GHz Doppler radar based stethoscope has been modified for non-contact diagnosis of heart sounds in a high-noise environment. By adding a digital single-sideband (SSB) modulator, the very low-frequency and difficult to hear heart sounds detected by this stethoscope were shifted toward the more sensitive part of the human ear's frequency response.In a quiet environment, the heart sounds heard by the modified radio frequency (RF) stethoscope are shown to be the same as those heard by a conventional stethoscope. However, the modified RF stethoscope has an advantage in an extremely high noise environment, where a conventional stethoscope cannot be used. Under those conditions, the quality of the RF stethoscope's acoustic response is shown to remain substantially unchanged.