Measurement system with real time data converter for conversion of I2S data stream to UDP protocol data

Abstract

A central goal of systems neuroscience is to simultaneously measure the activities of all achievable neurons in the brain at millisecond resolution in freely moving animals. This paper describes a protocol converter which is part of a measurement acquisition system for multichannel real time recording of brain signals. In practice, in such techniques, a primary consideration of reliability leads to great necessity towards increasing the sampling rate of these signals while simultaneously increasing the resolution of A/D conversion to 24 bits or even to the unprecedented 32 bits per sample. In fact, this was the guiding principle for our team in the present study. By increasing the temporal and amplitude resolution, it is supposed that we get enabled to discover or recognize and identify new signal components which have previously been masked at a "low" temporal and amplitude resolution, and these new signal components, in the future, are likely to contribute to a deeper understanding of the workings of the brain.

Physical Validation of a Residual Impedance Rejection Method during Ultra-Low Frequency Bio-Impedance Spectral Measurements

“…MCU1 is the master unit and is programmed to: receive the measurement commands through a universal asynchronous receiver–transmitter (UART1) peripheral sent by the personal computer (PC) user with the help of the graphical user interface (GUI); both set up and establish the communication [ 35 ] with the external digital-to-analog converter (DAC); calculate and transmit the excitation signal to the DAC; and receive the measurement results of MCU2 by UART2 and send these back to the GUI by UART1. …”

“…both set up and establish the communication [ 35 ] with the external digital-to-analog converter (DAC);…”

“…In the 10–100 kHz range, ksample/s is used; while, in the 1 mHz–10 kHz frequency range, the signals are sampled at ksample/s. If ksample/s sampling is executed, then the data handling for real-time calculations is realized with ping-pong buffering, as discussed in [ 35 ]; In each decade during the sweeping measurement, the number of excitation frequencies can be chosen between 3 and 100 (the frequency values are selected equidistantly on the logarithmic scale); A first-order complementary filter-based band-pass filter smooths the raw ADC signals before the execution of the lock-in algorithm (this feature can be turned on and off in the GUI). In the presented measurements, these filters were turned off; The executed algorithm contains low-pass filters after the signal multiplications, which can be also turned on and off in the GUI.…”

“…In the 10–100 kHz range, ksample/s is used; while, in the 1 mHz–10 kHz frequency range, the signals are sampled at ksample/s. If ksample/s sampling is executed, then the data handling for real-time calculations is realized with ping-pong buffering, as discussed in [ 35 ];…”