Question

functional block of EEG draw and explain

and state range of probe of EEG

explain it in simple way

Answer 1

Concept required- EEG or Electro Encephalo Gram is a test which is used to find out about the bio potential of the brain.

Solution -

The block diagram of EEG is shown as below -

Subject head with Amplifiers Chart drive and Electrode montage 10-20 electrode Representation on chart and Filters writer unit selector placement ADC Computer Oscilloscope EEG representation on Computer monitor BLOCK DIAGRAM OF EEG

Now let's see the explanation of this block diagram -

1. Montage selector- This selects a channel out of many that convey different info. The 10-20 electrode is symmetrically placed due to the fact that Montages are also. symmetrical. The montage selector consists many switches of which the user can select any.
2. Pre-Amplifier - They amplifies the low amplitude level ( of micro-volt range ) into some range which can be worked with easily in processing stage. High gain , High CMRR operational amplifier is generally used for this purpose
3. Filters and amplifiers - The noise from the muscle artifacts make reading untrustworthy. So the filters removes this noise and amplifies them to improve the amplitude of EEG waveform.
4. Writing recorder and paper drive -   The main task of writing is done by ink type writing recorder, where the recorder is a chart paper. A stable paper drive mechanism gives for an accurate EEG waveform
5. Analog and Digital Converters (ADC) - They convert analog EEG signals into the digital signals which can be used by the computers as the computers can only understand digital signals
6. Oscilloscope - It is generally used to see the EEG waveform in a digital format. This can be stored and saved for future reference.

Now let's see the frequency range of the EEG.

1. Gamma - It has frequency in the range of 30 - 100 HZ
2. Beta - It has range 12- 30 Hz
3. Alpha - It has range 8-12 Hz
4. Theta - It has range 4-7 Hz
5. Delta - It has range 0-4 Hz

And that's how we get the answer :0