English: In the picture above, we take note of the various axes. The y-axis is the frequency response |H(ω)| and the x-axis are the various radian frequencies, ω_i. We note the two frequences marked on the x-axis, ω_p and ω_s. ω_p indicates the pass band cutoff frequency and ω_s indicates the stop band cutoff frequency. The two dashed lines on the top left of the graph indicate the δ_p and the two dashed lines on the bottom right indicate the δ_s. All other frequencies listed indicate the extremal frequencies of the frequency response plot. As a result there are six extremal frequencies, and then we add the pass band and stop band frequencies to give a total of eight extremal frequencies on the plot.