DEVICE FOR INVESTIGATING AGGREGATION PROPERTIES OF BIOLOGICAL OBJECTS Russian patent published in 1994 - IPC

FIELD: medicine. SUBSTANCE: device has thermostated cuvette section 1 including cuvettes 2 and 3, mixing magnetic member 4, light sources 5 and 6 and photodetectors 7 and 8, current sources 9 and 10, preamplifiers 11 and 12, subtraction unit 13, controllable amplifier 14, clock pulse generator 15, frequency dividers 16 and 31, AND gate 17, pulse counter 18, digital-analogue converter 19, comparators 20 and 28, low-pass filters 21 and 32, recording unit 22, START button 23, pulse shaper 24, semiconductor diode 25, integrating analogue-digital converter 26, digital indicator 27, reference voltage source 29, mixing unit 30, controllable phase shifter 33, power amplifier 34, synchronous electric motor 35 and permanent magnet 36. The light sources are switched-on only during first cycle of operation of analogue-digital converter 26. Upon pressing Start button 23 calibration of the device is carried out during which at the output of amplifier 14 a predetermined voltage is set due to feedback effect. During second operating cycle of the analogue-digital converter at the output of comparator 20 a pulse duration of which is proportional to the voltage value at the output of amplifier 14 during the first operating cycle occurs. During third operating cycle the voltage at the output of amplifier 14 is stored with the light sources switched off. This voltage occurs as a result of instabilities of measuring path components and illumination of the cuvette section. Then this voltage is automatically subtracted in the analogue-digital converter during the first cycle. Synchronization of the processes of mixing and deriving measurement information is effected due to the fact that supply voltages of electric motor 35 is strictly synchronized with cycle of the operation of the analogue-digital converter. Power supply phase of electric motor 35 is controlled by phase shifter 33 as to noise minimum at recording signals in recording unit 22. EFFECT: enhanced efficiency, and reliability. 3 cl, 4 dwg