PDF (Trace Data)
shows the Probability Density Function of the selected channel. PDF 1) Probability Density Function Trace Data, or 2) Portable Document Format (PDF) created by Adobe Systems is an open standard for document exchange. indicates the probability that a given level has occurred.
is equivalent to a normalized histogram. A histogram shows how the amplitude of a signal is distributed between its maximum and minimum values. Amplitude is shown on the X-axis. Number of counts is shown on the Y-axis.
The number of averages for a histogram determines the number of counts in the histogram; in other words, how many records are measured¾the records are not "averaged". If averaging is off or if exponential averaging is selected, the measurement continues indefinitely. Keep in mind that the accuracy of the histogram is dependent on the frequency span, time-record length, and number of averages (if averaging is on).
Histograms are used for such things as determining the statistical properties of noise and monitoring the performance of electromechanical positioning systems.
trace data is normalized by multiplying the number of averages by the number of points in the time record, then dividing this value by the DV spacing on the X-axis. The probability of a signal falling between two points is equal to the integral of the curve between those points.
trace data displays the number of points used in its computation above the trace (). It also displays the average level () above the trace.
