Fig. 18

(a) Amplitude spectrum of the output voltage recorded from the AFE of the proposed instrument, the DP-301 Warner differential amplifier and the bioamplifier included in the Powerlab 26 T data acquisition system when two sinusoidal single tones (5 Hz and 25 Hz, amplitude 100 nV peak) were injected sequentially to the inputs of the instruments. The outputs of the three instruments were sampled at 1 kSPS. (b) Amplitude spectrum of the output voltage recorded from the thee instruments when two sinusoidal single tones (5 Hz and 25 Hz, amplitude 30 nV peak) were injected sequentially to the inputs of the instruments. The outputs of the three instruments were sampled at 1 kSPS. (c) It is clear that the AFE of the proposed instrument and the bioamplifier can accurately record the weak sinusoidal tone, whereas the DP-301 differential amplifier detects the tone but it cannot provide an accurate recording. (d) As in the case of the 100 nV peak sinusoidal tone, only the AFE of the proposed instrument and the bioamplifier can precisely record the 30 nV peak sinusoidal tone. It is important to note here that the noise floor of the proposed instrument is lower than the noise floors of the other two instruments