QS. An electroencephalogram (EEG) records the bioelectrical activity of the brain. The typical amplitude of an EEG signal is luV to 100V. However, in general, there are many activities that are recorded at the brainwave at one instance. In order to diagnose the listening ability of the ear, a loud sound is fed to the ear and the EEG response from this event is recorded.*** [25 marks) Name two best locations to place the EEG electrodes so that the signal obtained is the largest. Also state the name of this diagnostic test and the type of brain activity that is focused on [3 marks] (b) Draw the complete block diagram of a single-channel EEG biopotential amplifier. Label the electrical and frequency specifications for every block. [7 marks) (c) Determine the number of gain stages and calculate the gain for every stage. Assume the system is powered with a 10V dual supply and the desired EEG output is 5V. (5 marks) (d) Draw the schematic of a high-pass and low-pass filter both of which are 4ch order each. [5 marks) (e) Draw the circuit of the EEG instrumentation amplifier (with three-op-amps). Calculate the CMRR of this amplifier given that the EEG output is 0.25 mV (to a 10 pV differential EEG input) and the noise output is 0.0005mV (to a 10 u V common-mode noise input). A single op-amp amplifier can also be used to amplify the EEG signal but with some drawbacks. Discuss the disadvantage of this amplifier as compared to this instrumentation amplifier. [5 marks) QS. An electroencephalogram (EEG) records the bioelectrical activity of the brain. The typical amplitude of an EEG signal is luV to 100V. However, in general, there are many activities that are recorded at the brainwave at one instance. In order to diagnose the listening ability of the ear, a loud sound is fed to the ear and the EEG response from this event is recorded.*** [25 marks) Name two best locations to place the EEG electrodes so that the signal obtained is the largest. Also state the name of this diagnostic test and the type of brain activity that is focused on [3 marks] (b) Draw the complete block diagram of a single-channel EEG biopotential amplifier. Label the electrical and frequency specifications for every block. [7 marks) (c) Determine the number of gain stages and calculate the gain for every stage. Assume the system is powered with a 10V dual supply and the desired EEG output is 5V. (5 marks) (d) Draw the schematic of a high-pass and low-pass filter both of which are 4ch order each. [5 marks) (e) Draw the circuit of the EEG instrumentation amplifier (with three-op-amps). Calculate the CMRR of this amplifier given that the EEG output is 0.25 mV (to a 10 pV differential EEG input) and the noise output is 0.0005mV (to a 10 u V common-mode noise input). A single op-amp amplifier can also be used to amplify the EEG signal but with some drawbacks. Discuss the disadvantage of this amplifier as compared to this instrumentation amplifier. [5 marks)
