V.O. Molodtsov – Ph.D.(Eng.), Associate Professor, St.Petersburg Electrotechnical University
V.Y. Smirnov – Post-graduate Student, St.Petersburg Electrotechnical University
S.D. Solnushkin – Senior Research Scientist, Pavlov Institute of Physiology RAS (St.-Petersburg)
V.N. Chikhman – Ph.D.(Eng.), Head of Laboratory, Pavlov Institute of Physiology RAS (St.-Petersburg)
The new hardware and software modules for neurophysiological experiments are presented. Previously number of tools for computer support of experiments has been introduced for systems based on IBM PC. This were ADC of differing digit capacity and performance for ISA-bus (MD42, MD142, MD70, MD88, MD93, MD32), amplifiers (MD90, MD95, MD42U), module for input of interpulse intervals (MD79), remote control system for input responses (MD74). Modules had high metrological characteristics, autoadjustment Bias zero and nonlinearity.
Recently, a new class of sigma-delta ADC with wide dynamic range and digital filtering functions has appeared as the basis for measuring instruments for the next generation. Device MD155 was provided for converting to digital code of low frequency signals on eight channels, as well as input-output digital signals. To register of visual evoked potentials a portable device MD171 with 26 measuring channels was created, characterized by the presence of a separate ADC chip for each channel. The device MD226 was created for measuring signals with transfer of results via Bluetooth to a PC. The radio module is implemented on a chip WT11 (BlueGIGA ), adjusts parameters and the transfer of measurement results. MD226 module is based on ADC ADS1298, focused on biomedical applications. Programmable structure allows realizing standard wiring diagrams for reference electrode, adopted in cardiography and encephalography. Microcontroller implemented on a chip ATtiny167 performs the functions of the block management unit. MD236 device designed to monitor changes in the frequency of impulse activity of neurons when exposed to a biological object. The device counts the pulses that have an amplitude greater than a certain threshold voltage and the input received during a certain period of time. Communication via the USB interface is implemented on a chip FT245RL. The basic units of the device performed on chip programmable logic EPM570T100C5. MD228 is designed for generating pulses of a certain frequency, amplitude, and duty cycle. It has four independent channels. It is possible modulation of top-level variable voltage pulses linearly (LIN). MD245 device designed for use in the assessment of the functional state of human respiratory muscles. All the digital part of the device is made on a chip CPLD EPM570T100C5 (Altera).
Software support for designed devices is organized by a driver. In the Delphi environment using DirectX program designed to control the equipment, processing and visualization of signals, control experiment in interactive mode. Digitized processes are stored in a relational database. Programs include procedures for digital filtering, scaling axes (used functions of Matlab).
To carry out psychophysical experiments to study visual perception a number of programs for synthesis and presentation of images are realized.
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