V.I. Shereshkov, T.E. Shumilova, A.D. Nozdrachev

Overwhelming majority of existing detectors for registration of pressure, temperature, mechanical efforts and other physical processes are analogue transducers of quantities being measured into electric signal. The considerable number of similar detectors now available can be efficiently used for investigation of blood circulation, breathing, nervous system activity and some other systems of organism without using complicated expensive digital technology with its bulky software. Bioelectric signals (ECG, EEG, EMG etc.) are essentially small in magnitude and refer to the sphere of infra-low frequency. For their adequate registration it is important to choose the definite system of getting signal, the type of electrodes and parameters of amplifiering technical equipment. Of great interest is the usage of instrumentation amplifiers, for example, AD620, having high entrance impedance, effective suppression of synphase interferences, low level of noise and other characteristics, which are required for bioamplifiers of general usage.As far as the constructive design is concerned, the amplifier has only one external element, which regulates amplifying coefficient factor. When registering non-electric physiological indices various methods of their transformation into electric signals can be used. Of most commonly used transducers are tenzoresistant and thermoresistant ones, as well as photodetectors, on the basis of which - when using modern electronic technology - a great number of detectors are produced for registration of parameters of gemodynamics, hydraulic pressure , muscle contractions etc. A lot of devices for medical and physiological purposes for registration of blood pressure, breathing parameters, pulse frequency, oxygen consumption etc. are designed on the basis of such transducers. The electric scheme of transducers tends to have a measuring bridge, as well as an amplifier, for which it is convenient to use instrumental amplifiers. Telemetric transmission of information is of great interest for developing physiological methods of investigation. Even though these methods began their origin in the middle of the last century, practical designs appeared not long ago. That said, the availability of considerable modern base of electronic components and large park of non-expensive receivers, give us the objective possibility for the rapid development in the sphere of wireless registration of physiological indices. The article contains practical schemes of devices for registration of ECG, blood pressure, muscle contractions, telemetric transmission of cardiac activity etc., as well as the examples of the records of processes being studied.