2
The product is powered by 4 AAA internal batteries.
1.3 OPERATING PRINCIPLE
Fetal Doppler consists of probe (transmitter and receiver) and signal
process unit.
Ultrasonic wave is transmitted from one piezoelectric ceramic at the front
of the probe to the uterus of the pregnant women. Echo is received by
the other piezoelectric ceramic at the front of the probe when ultrasonic
wave reaches the fatal heart. Then it is converted into voltage. This
Doppler signal is detected and demodulated from the received signal.
And the Doppler frequency is consistent with the rhythm of the fetal
systole and diastole. Once cardiac valves vibrate and a Doppler
frequency excursion is formed. It is transmitted an output signal of
cardiac valves vibrating, and it is sent to the loudspeaker for getting a
rhythmical sound with the fetal heartbeat. Simultaneously, it is sent to a
counter which calculate periods of heartbeat that is fetal heartbeat rate
(bpm=beat per minute).
SECTION 2: SAFETY GUIDANCE
2.1 INDICATIONS FOR USE
The product is normally applied to fetus above twelve weeks growth,
difference in pregnant mater. The normal range of fetal heart rate:
110bpm-160bpm.
Listen to SFH:
The sound of fetal heartbeat can be recorded by a recorder
which is connected with the product.
Play Music:
Operator can play the music saved in the product from the
speaker.
Record SFH:
The product’s record model can record the sound of the fetal
heartbeat.
Playback SFH:
Operator can playback the sound of the fetal heartbeat saved
in the Product‘s record model.
Transient FHR:
