3.  Sensor (S)–converts arbitary physical quantity into electric signal  Adaptor (A)–provides signal amplification to a required level; expands a dynamic range of input signal; sensor adjustment and other DCP channel elements according to the load.  Normalization circuit (NC)– is used as a filter, unwanted low-frequency and high frequency components are removed from the signal

4.  Functional conversion (FC) of analog signal is carried out in order to implement units in sensor structure to display definite mathematical operations and improve its accuracy parameters.  Sample and hold device(SHD) – is used to store analog signal for a transformation time period of ADC  Analog-to-digital converter (ADC) –transforms analog signal into a digital code

5.  Digital switch (DS) – selects a channel and transmits data to a microprocessor.  Microprocessor (MP) – on the one hand, it is a complex program-driven device, on the other hand, it is an enormous integrated circuit.

6.  Operational amplifier (OA) – is an analog integrated environment (IE), voltage is formed on its output, this voltage is equal to a gain difference between two input voltages.

7. OA is totally insensitive to any components of input signals common to both OA inputs. It is called a common- mode signal and is given by

8. Ideal frequency selective filter– a device or system which has a gain- transfer characteristic between input and output; it is constant in a certain frequency bandwidth and there is a naught output in a stopband. Advantages of an active filter compared with a passive filter :  Gain. The active filter with a maximum gain-transfer characteristic can be greater than unity.  Minimal load impact. A gain-transfer characteristic of an active filter is practically independent of the load the filter works for and a source that controls the filter.  Non-inductive filters. To design an active filter only resistors and capacitors are required, inductance is not required. This feature is particularly important when operating at relatively low frequencies (<10 Hz), otherwise it would require larger inductance.

9.  Comparator – a circuit that compares two input voltages U вх and U оп ; it generates output voltage Uo=Uh, if U вх ˃ U оп and Uo=Ul if U вх  U оп, where Uh и Ul - two fixed voltage levels (high and low).

10.  To store changing analog signals for the time of conversion, switching and other operations in data collection systems a sample and hold circuit is used