comm.GeneralQAMModulator
Modulate using arbitrary QAM constellation
Description
The GeneralQAMModulator object modulates using
quadrature amplitude modulation. The output is a baseband representation
of the modulated signal.
To modulate a signal using quadrature amplitude modulation:
Define and set up your QAM modulator object. See Construction.
Call
stepto modulate a signal according to the properties ofcomm.GeneralQAMModulator. The behavior ofstepis 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.GeneralQAMModulator creates a
modulator System
object, H. This object modulates
the input signal using a general quadrature amplitude modulation (QAM)
method.
H = comm.GeneralQAMModulator( creates
a QAM modulator object, Name,Value)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).
H = comm.GeneralQAMModulator(CONST, creates
a General QAM modulator object, Name,Value)H. This object
has the Constellation property set to CONST,
and the other specified properties set to the specified values.
Properties
|
Signal constellation Specify the constellation points as a vector of real or complex
double-precision data type. The default is exp().
The length of the vector determines the modulation order. The |
|
Data type of output Specify the output data type as one of |
Methods
| step | Modulate using arbitrary QAM constellation |
| Common to All System Objects | |
|---|---|
release | Allow System object property value changes |
Examples
Modulate data using an arbitrary 3-point constellation. Then, visualize the data in a scatter plot
hQAMMod = comm.GeneralQAMModulator;
% Setup a three point constellation
hQAMMod.Constellation = [1 1i -1];
data = randi([0 2],100,1);
modData = step(hQAMMod, data);
scatterplot(modData)
Algorithms
This object implements the algorithm, inputs, and outputs described on the General QAM Modulator Baseband block reference page. The object properties correspond to the block parameters.