System object: comm.GeneralQAMDemodulator
Package: comm
Demodulate using arbitrary QAM constellation
Y = step(H,X)
Y = step(H,X,VAR)
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.
Y = step(H,X) demodulates the input data, X,
with the general QAM demodulator System object, H,
and returns Y. Input X must
be a scalar or a column vector with double or single precision data
type. When you set the BitOutput property to true
and the DecisionMethod property to 'Log-likelihood
ratio' the input data type must be single or double precision. Depending
on the BitOutput property value, output Y can
be integer or bit valued.
Y = step(H,X,VAR) uses soft decision demodulation
and noise variance VAR. This syntax applies when
you set the BitOutput property to true, the DecisionMethod property
to Approximate log-likelihood ratio or Log-likelihood
ratio, and the VarianceSource property
to 'Input port'.
Note
obj specifies the System object on
which to run this step method.
The object performs an initialization the first time the step method
is executed. This initialization locks nontunable
properties and input specifications, such as dimensions,
complexity, and data type of the input data. If you change a nontunable
property or an input specification, the System object issues an
error. To change nontunable properties or inputs, you must first call
the release method to unlock the object.