A portable apparatus for the non-invasive, simultaneous, self-testing of fetal and maternal signals which comprises: a user display means to indicate that the device is operational, an ultrasonic means to detect fetal heart rate connected to said device, a detection means for maternal input signal connected...http://www.google.com/patents/US5257627?utm_source=gb-gplus-sharePatent US5257627 - Portable non-invasive testing apparatus
