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System object: comm.CCDF
Package: comm

Get relative power value for a given probability


R = getPercentileRelativePower(H,P)


R = getPercentileRelativePower(H,P) finds the relative power values, R. The power of the signal of interest is above its average power by R dB (if PowerUnits equals 'dBW', or 'dBm') or by a factor of R (in linear scale if PowerUnits equals 'Watts') with a probability P.

The method output R, is a column vector with the i-th element corresponding to the relative power for the i-th input channel. The method input P can be a double precision scalar, or a vector with a number of elements equal to the number of input channels. If P is a scalar, then all the relative powers in R correspond to the same probability value specified in P. If P is a vector, then the i-th element of R corresponds to a power value that occurs in the i-th input channel, with a probability specified in the i-th element of P.

For the i-th input channel, this method evaluates the inverse CCDF curve at probability value P(i).


Obtain CCDF curves for a unit variance AWGN signal and a dual- one signal. The AWGN signal is RPW1 dB above its average power one percent of the time, and the dual-tone signal is RPW2 dB above its average power 10 percent of the time. This example finds the values of RPW1 and RPW2.

 n = [0:5e3-1].';
 s1 = randn(5e3,1);                    % AWGN signal
 s2 = sin(0.01*pi*n)+sin(0.03*pi*n);   % dual-tone signal
 hCCDF = comm.CCDF;                    % create a CCDF object
 step(hCCDF,[s1 s2]);                  % step the CCDF measurements
 plot(hCCDF)                           % plot CCDF curves
 RPW = getPercentileRelativePower(hCCDF,[1 10]);
 RPW1 = RPW(1)
 RPW2 = RPW(2)
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