Convolutionally encode binary data and map using arbitrary QAM constellation
The GeneralQAMTCMModulator
object implements
trelliscoded modulation (TCM) by convolutionally encoding the binary
input signal. The object then maps the result to an arbitrary signal
constellation. The Signal constellation property lists the signal
constellation points in setpartitioned order.
To modulate a signal using a trelliscoded, general quadrature amplitude modulator:
Define and set up your general QAM TCM modulator object. See Construction.
Call step
to modulate a signal
according to the properties of comm.GeneralQAMTCMModulator
.
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.
H = comm.GeneralQAMTCMModulator
creates
a trelliscoded, general quadrature amplitude (QAM TCM) modulator System object, H
.
This object convolutionally encodes a binary input signal and maps
the result using QAM modulation with a signal constellation specified
in the Constellation property.
H = comm.GeneralQAMTCMModulator(
creates
a general QAM TCM modulator System object, Name
,Value
)H
,
with each specified property set to the specified value. You can specify
additional namevalue pair arguments in any order as (Name1
,Value1
,...,NameN
,ValueN
).
H = comm.GeneralQAMTCMModulator(TRELLIS,
creates
a general QAM TCM modulator System object, Name
,Value
)H
.
This object has the TrellisStructure
property set
to TRELLIS
, and the other specified properties
set to the specified values.

Trellis structure of convolutional code Specify trellis as a MATLAB^{®} structure that contains the
trellis description of the convolutional code. Use the 

Termination method of encoded frame Specify the termination method as one of When you set this property to When you set this property to When you set this property to 

Enable modulator reset input Set this property to 

Signal constellation Specify a double or singleprecision complex vector that lists the points in the signal constellation that were used to map the convolutionally encoded data. You must specify the constellation in setpartitioned order. See documentation for the General TCM Encoder block for more information on setpartitioned order. The length of the constellation vector must equal the number of possible input symbols to the convolutional decoder of the general QAM TCM demodulator object. This corresponds to 2^{N }for a rate K/N convolutional code. The default corresponds to a setpartitioned order for the points of an 8PSK signal constellation. This value is expressed exp($$2\times \pi \times j\times \raisebox{1ex}{$[\begin{array}{cccccccc}0& 4& 2& 6& 1& 5& 3& 7\end{array}]$}\!\left/ \!\raisebox{1ex}{$8$}\right.$$). 

Data type of output Specify the output data type as one of 
step  Convolutionally encode binary data and map using arbitrary QAM constellation 
This object implements the algorithm, inputs, and outputs described on the General TCM Encoder block reference page. The object properties correspond to the block parameters.
comm.GeneralQAMTCMDemodulator
 comm.GeneralQAMModulator
 comm.PSKTCMModulator
 comm.ConvolutionalEncoder