| 摘要 |
A compact fetal sound system delivers high-fidelity sound to a fetus in utero through a miniature, abdominally mounted driver with a convex diaphragm. No gel is necessary at the interface between the diaphragm and the mother's abdomen. Digital signal processing shapes the frequency spectrum of the sound transmitted to the fetus, so that after traveling through the attenuative tissue of the expectant mother the desired volume of sound and frequency content reach the ears of the fetus. As the term of pregnancy progresses, the frequency shaping provided by the digital signal processing automatically varies to compensate for changes in uterine lining thickness and the like. Preferred embodiments also include a microphone attached to the abdomen of the mother and signal processing to correct for frequency and amplitude distortions of sound eminating from the womb. Embodiments also include an elastic belt to maintain the transducer and microphone against the abdomen.
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