# getProbability

(Not recommended) Probability of relative power value using CCDF

`comm.CCDF` is not recommended. Use `powermeter` instead. For information on updating your code, see Version History.

## Syntax

``P = getProbability(ccdf,R)``

## Description

example

``` `P = getProbability(ccdf,R)` returns the probability, as a percentage in the range [0, 100], that the power level of a signal is above its average power by the specified level `R`. The input `ccdf` specifies the complementary cumulative distribution function (CCDF) curves of the signal of interest. For the ith channel in the input signal, the function evaluates the corresponding CCDF curve at relative power value `R`(i).Before calling the `getProbability` function, you must obtain the CCDF curves of the signal of interest by calling the `ccdf` System object™ on the signal.```

## Examples

collapse all

Generate a unit variance AWGN signal and a dual-tone signal.

```n = [0:5e3-1].'; s1 = randn(5e3,1); % AWGN signal s2 = sin(0.01*pi*n) + sin(0.03*pi*n); % Dual-tone signal```

Create a CCDF measurement object.

`ccdf = comm.CCDF;`

Obtain the CCDF curves of the signals.

`ccdf([s1 s2]);`

Plot the resulting CCDF curves.

```plot(ccdf) legend('AWGN','Dual-tone')```

Find the probability that the AWGN signal power is 5 dB above its average power and the probability that the dual-tone signal power is 3 dB above its average power.

`P = getProbability(ccdf,[5 3])`
```P = 2×1 7.9551 21.1421 ```

## Input Arguments

collapse all

CCDF measurements, specified as a `comm.CCDF` System object. The object must contain CCDF curves. To obtain CCDF curves, call the object on the input signal of interest.

Relative power value, specified as one of these options.

• Numeric scalar — The function evaluates each CCDF curve at the relative power value `R`.

• Numeric row vector — The function evaluates the ith CCDF curve in the input `ccdf` at relative power value `R`(i).

The `PowerUnits` property of the object specifies whether the relative power value is returned in a dB scale or linear scale.

Data Types: `double`

## Output Arguments

collapse all

CCDF probability of the relative power value, returned as a numeric column vector with values in the range [0, 100]. A value of 100 corresponds to a probability of 1.0. `P`(i)/100 is the probability value of the channel corresponding to the ith CCDF curve in the input `ccdf`.

Data Types: `double`

## Version History

Introduced in R2012a

expand all