PRACTICAL NO:1

AIM: To study EEG SIMULATOR

Material required-

[1] Matrix trainer kit-EEG SIMULATOR

[2]DIGITAL STORAGE CRO

EEG SIMULATER

The brain generates rhythmical potentials in the individual neurons of the brain. These

potentials get summated as millions of cell discharge synchronously and appear as a

surface waveform, known as the electroencephalogram. The EEG signal can be

produce by means of electronics components. The integrity of these components,

which produce artificial EEG signal, is known as EEG SIMULATOR.

Fig below shows the EEG signal.

Fig:1.1. EEG waveforms

CIRCUIT DESCRIPTION:

The practical circuit of the EEG simulator is shown in fig 1. The EEG simulator

circuit consists of following block

Noise Generator:

The block of circuit generates random frequencies from 0.1 Hz to 100 kHz. Zener

diode DZ produce junction noise when it is forward biased. This noise is amplified by

Q1. Further does op-amp A1 amplify noise signal with the gain 10-100. Set by

AMPLITUTDE P1.

This signal is further in six band of frequency to active EEG signal & five different

EEG band.

Band Pass Filter for 0.5Hz to 30Hz: this is made up of A2 &A3 both Op-amp from

two-signal order band pass filter for same frequency. Output of this circuit is

simulating EEG signal.

Band Pass Filter for 0.5Hz to 4Hz: this is made up of A4 &A5 both Op-amp from

two-signal order band pass filter for same frequency. Output of this circuit is

simulating EEG signal.

Band Pass Filter for 4Hz to 8Hz: this is made up of A6 &A7 both Op-amp from

two-signal order band pass filter for same frequency. Output of this circuit is

simulating EEG signal.

Band Pass Filter for 8Hz to 13Hz: this is made up of A8 &A9 both Op-amp from

two-signal order band pass filter for same frequency. Output of this circuit is

simulating EEG signal.

Band Pass Filter for 13Hz to 22Hz: this is made up of A10 &A11 both Opamp from

two-signal order band pass filter for same frequency. Output of this circuit is

simulating EEG signal.

Figure: 1.2: The circuit diagram of EEG simulator

Band Pass Filter for 22Hz to 30Hz: this is made up of A12 &A13 both Opamp from

two-signal order band pass filter for same frequency. Output of this circuit is simulate

EEG signal.

PROCEDURE:

Setup –

[1] Keep the POWER switch in off condition

[2] Connect power chord to main (230 volt A.C)

[3] Put “ON” the trainer kit & CRO.

[4] Observe the output at test pints T1,T2,T3.T5,T6,T7,T8,T9&T10 w.r.t ground

[5] Note Waveform for all band frequencies.

[6] Feed output from kit through test points A,G&R to EEG system and record the o/p

of EEG signal

[7] Vary the amplitude of signal to calibrate the EEG system.

Conclusion: