Method and System for Data Synchronization

Abstract

A system for monitoring includes: multiple EEG sensors spatially positioned on a layer of tissue for capturing EEG signals of a patient; multiple amplifiers coupled with the EEG sensors for amplifying the captured signals; and a low frequency oscillator for generating a synchronizing signal which is distributed to the amplifiers for synchronizing the digitization of the captured signals; wherein each amplifier includes: a voltage controlled oscillator for an adjustable frequency reference; an analog to digital converter for converting the amplified signal to a digital value; and a microcontroller for controlling the frequency of the voltage controlled oscillator and operation of the analog to digital converter by using the synchronizing signal.

We claim: 
     
         1 . A method for synchronizing EEG signals measured by an EEG monitoring system, wherein the EEG monitoring system comprises a plurality of EEG sensors positioned on a layer of tissue and wherein each of the plurality of EEG sensors is configured to capture EEG signals of a patient, at least one amplifier coupled to each of the plurality of EEG sensors and configured to amplify the captured EEG signals, and a first oscillator, wherein the at least one amplifier comprises an input for receiving a synchronizing signal from the first oscillator, the method comprising:
 distributing the synchronizing signal from the first oscillator to each of the at least one amplifier;   measuring a period of the synchronizing signal;   adjusting a second oscillator, having a frequency, in the at least one amplifier to match a timer count based on the period of the synchronizing signal;   determining a function of the frequency of the second oscillator frequency to produce a clock signal; and   adjusting a frequency of each of the second oscillators such that the frequencies of the second oscillators are identical.   
     
     
         2 . The method of  claim 1 , wherein the first oscillator is configured to generate the synchronizing signal having a frequency in a range of 0.1 Hz to 10 kHz. 
     
     
         3 . The method of  claim 1 , wherein the second oscillator is voltage controlled. 
     
     
         4 . The method of  claim 1 , wherein the function of the frequency of the second oscillator frequency is determined by dividing the frequency to produce the clock signal. 
     
     
         5 . The method of  claim 4 , further comprising using the clock signal to drive the analog to digital converter clock signal. 
     
     
         6 . The method of  claim 4 , wherein the at least one amplifier comprises the second oscillator, the analog to digital converter coupled to the second oscillator and configured to digitize the captured EEG signals, and a microcontroller configured to control the frequency of the second oscillator and an operation of the analog to digital converter based on the synchronizing signal. 
     
     
         7 . The method of  claim 6 , wherein the microcontroller comprises a signal isolator and wherein the signal isolator comprises isolated DC-DC power converters. 
     
     
         8 . The method of  claim 1 , further comprising transmitting the amplified EEG signals to a computing device, wherein the computing device is configured to process the amplified EEG signals. 
     
     
         9 . The method of  claim 1 , wherein the synchronizing signal has a frequency of 1 Hz. 
     
     
         10 . The method of  claim 1 , wherein the microcontroller includes a digital to analog (DAC) converter and wherein the microcontroller is configured to adjust the second oscillator by setting the DAC to a corresponding voltage. 
     
     
         11 . The method of  claim 1 , wherein the at least one amplifier further comprises an internal timer having microsecond resolution and wherein the microcontroller is configured to measure a period of the synchronizing signal using the internal timer. 
     
     
         12 . The method of  claim 1 , wherein the at least one amplifier further comprises a filter configured to filter out high frequency noise, having a value range greater than 2 kHz, present in an analog voltage signal from the microcontroller output.