This allows for a meaningful comparison of different classes where the class widths may not be equal. The frequency density goes up the y-axis and the area of each bar will represent the frequency. Frequency of the time-domain signal.
Frequency Number of sampling units in which the species occurs Total number of sampling units employed for the study100.
The height of a rectangle is also equal to the frequency density of the interval ie the frequency divided by the width of the interval. Critical Frequency as a Function of Maximum Usable Frequency Formula. Frequency density of the fourth interval 15 5 30. By doing so the data are normalized to a single Hertz and a power spectral density is determined Figure 213.