Fig. 4From: Several insights into the preprocessing of electrograms in atrial fibrillation for dominant frequency analysisEffects of different pass band ranges on seeking DF. a The original signal; b the spectrum and DF of the signal after band-pass filtering of 40–250 Hz; c the spectrum and DF of the signal after band-pass filtering of 20–40 Hz; d the spectrum and DF of the signal after band-pass filtering of 20–100 Hz; e the spectrum and DF of the signal after band-pass filtering of 40–100 Hz; f the spectrum and DF of the signal after band-pass filtering of 200–400 Hz. Absolute value and LPF at 20 Hz are taken after band-pass filtering in graph b–f and the DF is marked out in these figuresBack to article page