INSTRUMENT FOR ULTRASOUND FETAL DIAGNOSTICS

摘要

The instrument is designed for the diagnostics and supervision of the heart activity. It has lower power consumption, is miniaturized and filtration is simplified. It improves the precision of recording the changes of the frequency of the heart rhythm (from 30 to 250 heart-beats a minute) on a wide range, regardless of the availability of strong disturbing signals. The instruments consists of quartz stabilized generator (1), high frequency power amplifier (2), transmitting piezoelectric resonator (3), receiving piezoelectric resonator (4), high frequency amplifier (5), frequency detector (6), first low-pase filter (7), low frequency amplifier (8), second low-pass filter (9), acoustic body (12), pulse formation circuitry (10) and indication circuit (11) with digital initialization of the measured results. The pulse shaping circuitry (10) is built of an enveloping detector (10-1) , comparator (10-2), frequency to voltage invertor (10-3), waiting multivibrator with controllable time-setting circuit (10-4), second waiting multivibrator (10-5) and RS-flip flop (10-6).