comm.ACPR System object

Package: comm

Description

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

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.

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

 clone Create ACPR measurement object with same property values getNumInputs Number of expected inputs to step method getNumOutputs Number of outputs from step method isLocked Locked status for input attributes and nontunable properties release Allow property value and input characteristics changes reset Reset states of ACPR measurement object step Adjacent Channel Power Ratio measurements

Examples

collapse all

Measure ACPR of a 16-QAM signal with symbol rate of 3.84 Msps

% Generate data with an alphabet size of 16 and modulate the data
x  = randi([0 16-1],5000,1);
hMod = comm.RectangularQAMModulator(16);
y = step(hMod,x);

% Usample 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
h = comm.ACPR(...
'SampleRate', 3.84e6*8,...
'MainChannelFrequency', 0,...
'MainMeasurementBandwidth', 3.84e6,...
'MainChannelPowerOutputPort', true,...
ACPR =

-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 = falseFmax = 1 if NormalizedFrequency = true