Documentation

# comm.ACPR

Adjacent Channel Power Ratio measurements

## Description

The ACPR System object™ measures adjacent channel power ratio (ACPR) of an input signal.

To measure adjacent channel power:

1. Define and set up your adjacent channel power object. See Construction.

2. Call step to measure the adjacent channel power ratio according to the properties of comm.ACPR. The behavior of step is specific to each object in the toolbox.

### Note

Starting in R2016b, instead of using the step method to perform the operation defined by the System object, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.

## Construction

H = comm.ACPR creates a System object, H, that measures adjacent channel power ratio (ACPR) of an input signal.

H = comm.ACPR(Name,Value) creates object, H, with each specified property set to the specified value. You can specify additional name-value pair arguments in any order as (Name1,Value1,...,NameN,ValueN).

## Methods

 reset Reset states of ACPR measurement object step Adjacent Channel Power Ratio measurements
Common to All System Objects
release

Allow System object property value changes

## Examples

expand all

Generate data with an alphabet size of 16 and modulate the data

x  = randi([0 15],5000,1);
y = qammod(x,16);

Upsample the data by L = 8 using a rectangular pulse shape

L = 8;
yPulse = rectpulse(y,L);

Create an ACPR measurement object and measure the modulated signal

acpr = comm.ACPR(...
'SampleRate', 3.84e6*8,...
'MainChannelFrequency', 0,...
'MainMeasurementBandwidth', 3.84e6,...
'MainChannelPowerOutputPort', true,...
ACPR = 1×2

-14.3659  -14.3681

mainChnlPwr = 38.8668

24.5010   24.4988

## Algorithms

### Note

The following conditions must be true, otherwise power measurements fall out of the Nyquist interval.

$\begin{array}{l}|MainChannelFreq±\text{​}\text{\hspace{0.17em}}\frac{MainChannelMeasBW}{2}|

Fmax = Fs/2 if NormalizedFrequency = false

Fmax = 1 if NormalizedFrequency = true