Figure 5.7.1. This is a screen shot of a computer program. The vertical axis is labeled Y value and goes from 0 at the bottom to 90 at the top. These are actually dB. Between every 10 dB mark are 5 smaller marks which are at 2 dB intervals. The horizontal axis is labeled X value and goes from minus 1 to plus 5 in steps of one. The frequency is 10 to the power of these numbers so the horizontal axis is really frequency on a log scale from 10 to the minus 1 to 10 to the 5. There are 4 curves on this graph. The red one starts at gain = 80 dB and frequency = 10 to the minus 1. It goes to the right and visibly falls away from the 80 dB line just past frequency = 1. It curves downward and is at 77 dB at 10 Hz. It straightens out and crosses through the point 60 dB and 100 Hz. It is now falling on a slope of minus 1 and passes through the points 40 dB, 1,000 Hz, 20 dB, 10,000 Hz, and 0 dB, 100,000 Hz. The green line starts on the left at 60 dB and 0.1 Hz. It falls away from the 60 dB line just to the right of 1 Hz. It passes through 57 dB at 100 hertz. It runs almost parallel with the red line and merges with it at two thirds of the way from 100 to 1,000 Hz. After that it follows the same path as the red line. The light blue line starts on the left at 59 dB and runs essentially parallel to the green line becoming curved at the same place. It passes through 56 dB at 100 Hz. It merges with the green line at about one third of the way between 100 and 1,000 Hz and merges with the red line at two thirds. The dark blue line begins merged with the light blue line. Dark drops below light just to the left of 10 Hz. It continues to fall below the light blue line and passes through 54 dB at 100 Hz. The dark blue line starts getting closer to the light blue line but more slowly then the others approached each other. The dark blue line finally merges with the other three about half way between 1,000 and 10,000 Hz. End verbal description.
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