| 摘要 |
<p>A portable ultrasonic Doppler System for sensing movement, e.g. fetal heartrate, within a body. A handheld unit (24) includes a housing containing an ultrasonic transmitter (38, 200) and an ultrasonic receiver (40, 212). The ultrasonic receiver detects ultrasonic energy emitted from the ultrasonic transmitter and reflected off of the moving object being monitored. The handheld unit also includes a radio frequency transmitter (222) for transmitting a carrier modulated in accordance with the response of the ultrasonic receiver. A radio frequency receiver unit (60), separate from the handheld unit (24), receives the signal broadcast by the handheld unit. The receiver unit (60), separate from the handheld unit (24), receives the signal broadcast by the handheld unit. The receiver unit drives a speaker (80) or earphone (68) to provide an audio output for listening to the moving object being monitored. Digital display and memory circuitry (400) is also provided which can be used in conjunction with said receiver unit to store and display data indicative of the movement being monitored. In conjunction with the handheld unit, a patient (22) being monitored becomes the radio frequency antenna ground plane, providing a highly efficient radio link between the handheld unit and the receiver unit.</p> |
