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Home arrow Departments arrow Biomeasurements arrow Department Implementations arrow BioLab STI - system for measurement of systolic time intervals of the cardiovascular system
BioLab STI - system for measurement of systolic time intervals of the cardiovascular system

BioLab STI device is one of the modules of the distributed measuring system BioLab and is intended for measurement and evaluation of systolic times of the cardiovascular system obtained from electrocardiogram (EKG), phonocardiogram (FKG) and carotidogram (KTG). 

BioLab system was designed for biosignal measurements in laboratory and experimental clinics. It consists of a set of intelligent sensors that are connected over the Ethernet network to a host PC working as a controlling and data processing unit. Each sensor contains specific measuring module for conditioning of signals from particular biophysical experiment and a controlling module based on Analog Devices ADμC812 microcontroller.


The BioLab STI (Systolic Time Intervals) device is a 3-channel measuring system intended for measurement and evaluation of systolic times of the cardiovascular system. These intervals are obtained from 3 recorded biosignals: electrocardiogram (EKG), phonocardiogram (FKG) and carotidogram (KTG) and are used for assessment of the functional state of the thyroid gland.The examination is based on the fact that hormones of the thyroid gland affect also the cardiovascular system. Evaluation of the systolic time intervals as peripheral indicators of the thyroidal function enables to deduce about normal thyroid gland function, about hypo- or hyperfunction. During the evaluation, pre-ejection period (PEP), time of the second reveberation (QS2) and heart rate (HR) are measured as shown in the figure. Using regression equations, it is also possible to estimate the overall thyroxine T4 level. The examination is sufficiently informative for screening purposes and for endocrinological diagniostics.  


Controlling module of the BioLab STI device is built around an ADµC812 microcontroller with necessary interface. To connect the sensor to the modular system over the Ethernet network, a RS232C to TCP/IP converter is used. To guarantee safety of the patient, BioLab ATR module is galvanically separated from the Ethernet network by optical isolation. The module is powered by a Li-ion cell that allows several hours of uninterrupted operation. In practical applications, intelligent power management allows working time of the cell up to tens of days. The module can by operated also during the battery charging from the power line 230V / 50 Hz, eventually even from the power line (without using the Li-ion cell).



Examinations performed using the BioLab STI and BioLab ATR devices can be evaluated together using common protocol and a circle diagram that is depicted with the BioLab ATR device. 

BioLab STI device is intended only for research and educational applications. It is not a medical device as defined in EU directive MDD 93/42/EEC. 

Basic technical data

ECG electrodes

3 single-use, selfadhesive pre-gelled Ag-AgCl electrodes connected by crocodile clips to shielded input cables

ECG amplifier

BF type input, voltage amplification programmable in the range 0 to 10000 (step 100), input impedance >10 GOhm, frequency response 0.16-1000 Hz (-3dB), CMRR >100 dB (50Hz), noise recalculated to input max. 15 mV p-p

Cardotidogram (KTG) sensor

piezoelectric pressure sensor MLT1010 Pulse Transducer from ADInstruments Pty Ltd, output 0 - 1 V, frequency response 2,5 - 5000 Hz

KTG amplifier

Programmable amplification 0 - 450, step 4,5, frequency response 0,16 to 1000 Hz

Phonocardiogram (FKG) sensor

microphone MLT201 Cardio Microphone from ADInstruments Pty Ltd, output range max. ħ10V (working range ħ5 mV), frequency response 10 to 600 Hz, dynamic range 0,01 - 10 m/s2 , sensitivity 100 V/ s2/m (at 100 Hz) 

FKG amplifier

Band pass filter for F1 zone (fo=35 Hz, -12dB at f1=17,5 Hz, f2=35 Hz), voltage amplification programmable in the range 0 to 10000, with step of 100.


Measurement Science Review (On-Line Journal)
Staff of Department of Biomeasurements