Spectrum Analyzer CCDF Measurements Panel
The CCDF Measurements panel displays complimentary cumulative distribution function measurements. CCDF measurements in this scope show the probability of the instantaneous power of a signal being a specified level above the average power of the signal. These measurements are useful indicators of the dynamic range of a signal.
To compute the CCDF measurements, each input sample is quantized to 0.01 dB increments. Using a histogram 100 dB wide (10,000 points at 0.01 dB increments), the largest peak encountered is placed in the last bin of the histogram. If a new peak is encountered, the histogram shifts to make room for that new peak.
To open this dialog box:
From the menu, select Tools > Measurements > CCDF Measurements
In the toolbar, click the CCDF Measurements
button.
Plot Gaussian reference — Show the complex white Gaussian noise reference signal on the plot.
Probability (%) — Percentage of the signal that contains the power level above the value listed in the dB above average column
dB above average — Expected minimum power level at the associated Probability (%).
Average Power — Average power level of the signal since the start of simulation or from the last reset.
Max Power — Maximum power level of the signal since the start of simulation or from the last reset.
PAPR — Ratio of the peak power to the average power of the signal. PAPR should be less that 100 dB to obtain accurate CCDF measurements. If PAPR is above 100 dB, only the highest 100 dB power levels are plotted in the display and shown in the distribution table.
Sample Count — Total number of samples used to compute the CCDF.
Reset — Clear all current CCDF measurements and restart.
