Ultrasound Doppler DFM-051 Solid state-portable Ultrasound frequency 2 MHz. Mains & battery operated. Housed in moulded ABS cabinet.   Principle of Operation :   The instrument works on the principle of Doppler Effect. Very low intensity Ultrasound of frequency 2 MHz is beamed in to body from a very small transducer which is reflected back from organs & blood particles. Reflected signal is changed slightly in frequency due to movement of foetal heart, blood particles & other moving organs. Reflected signal is received by the instrument, amplified & processed electronically to get audible signal through built in speaker or external earphone.   Specifications : Facility for Earphone & Tape Recording Operates on 6 Dry Cells Eveready 1050 type or can be operated on Mains Supply with Mains Adapter. Width:   217mm Height:   88mm Depth:   185mm Weight:   1.9 kg Obstetrical Applications Detection of foetal heart at 10 to 12 weeks Localization of Placenta. Detects Foetal Distress & Intrauterine death. Determine multiple pregnancies.