Power Spectrum Density for different time

  Bellow graphs taken for selecting which time is better for the study PSD of EEG signal.


  In the Fig 4.17 EEG data of channel taken for 1s. This data pass through the band pass filter for separating different frequency bands. For calculating the power spectrum density of each band we need to calculate the mean of all amplitudes present in the frequency band. In the delta band,  from the observations data it is seen that the amplitude of channel 6 is high as comparing the other channel. This channel present on the frontal lobe of the brain. For the channel seven amplitude man of frequency band suddenly deceasing. The position of this electrode is the right hemisphere of the brain. For this observation frontal part of right hemisphere is dominant, however it is seen that the subject doing the left side work. Generally the right hemisphere of the brain sees the work of the left side and vice versa. Next channel 8 amplitude mean is high which is placed on central lobe of the brain. In the theta and alpha band from the channel number 21 amplitude starts increasing. In the beta band these are small changes in the amplitude mean.
  As shown in the fig 4.17 observation taken for 1 second, the amplitude mean of the beta band is above 8uv. But when it takes for two second it is decreasing it is shown in the fig 4.18. In this reading it shows the dominant part for channel 6, it is in the frontal lode of the brain.
  For 1s observations after channel number 8 power density increases and decreases at the C1 channel but in this observations channel 9 and 10 power energy increases and after that decreases. In the previous observation for 1s it is absent but in this observation. But in this observation it shows the high amplitude. In the 1s observations theta band shows small changes in the amplitude but in the 2s observation it shows the good result at channel number 9 amplitude is high. From this observation it is seen that in delta band channel 6 is dominant in the frontal
side and channel 20 is dominant in the central lobe of the brain. Channel 16 power density is high at channel 16. In the theta band channel 9 power density is high in the central lobe of the brain which is belonging to the left hemisphere. Power spectrum density of channel 15 and 16 is high.
  For delta band, in the observations of the 1s and 2s power spectrum density of channel six is dominant. In this observation is same but in the 2s EEG data observation the power density
of channel is high but in the 4s EEG data observations the after the 6 number channel 12 has high power density which is belonging to the right hemisphere of central lobe. In theta band, in the first two observations for 1s and 2s EEG data this band not shows the high power density, but in these observations six number channel power densities is high. For alpha band and beta band there is dominant part.
  In this analysis good results are occurs. In the delta band, channel six is dominant is same like previous observations but for the channel 12 the power density is increased in the central lobe and decreased for channel 13. In theta band, power spectrum density is high for the channel six in the frontal lobe and channel 20 in the parietal lobe. In the power spectrum band alpha and beta has no dominant part. 


  These four observations conclude that the six second observation is good for the analysis of EEG data other than the 1s, 2s and 4s. Power spectrum densities of results are good for other observations.


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