Function menu button
④ MODE function menu button，press④ MODEto switch modes，There are four models to choose: 1, 2, 3, 4. （As showed in the upper left of LCDscreen）
MODE 1:Instantaneous fetal heart rate(FHR) display mode
MODE 2：Moving average FHR display mode（Slower than MODE 1 in FHR change in value）
MODE 3：Manual calculation FHR
MODE 4: the interface of backlighting switch setup, press ③ START/STOP to realize it.
Technical specificationsUltrasound frequency: 2.5MHz±3%
Overall sensitivity at the distances 200mm from the face of the probe: ≥90db
Spatial-peak temporal-peak acoustic pressure: 17.38mW/cm2
Effective area of the ultrasonic transducer active element: 1cm2
Output power: ＜5mW/cm2
Heart rate display range：50－210bpm
Power input：DC 8.4V 1.0A
Boundary dimension： 195×190×52mm
Host net weight：0.25Kg
Desirable characteristics of couplant ：density＝1.0g/cm2 velocity≤1.7m/s
impedance≤1.7×105g/cm2.s attenuation≤0.02dB/mm
The parametres of this product comply with the provisions of exemption，among
which are：Peak negative acoustic pressure：p－＜1MPa Sound intensity of
output beam： Iob ＜ 20mW/cm2 Spatial peak time average acoustic
intensity：Ispta＜100mW/cm2
