Package: comm
Estimate frequency offset for QAM signal
The QAMCoarseFrequencyEstimator
System object™ estimates
frequency offset for a QAM signal.
To estimate frequency offset for a QAM signal:
Define and set up your QAM Coarse Frequency Estimator object. See Construction.
Call step
to estimate
frequency offset for a QAM signal according to the properties of comm.QAMCoarseFrequencyEstimator
.
The behavior of step
is specific to each object in
the toolbox.
Note:
Starting in R2016b, instead of using the 
H = comm.QAMCoarseFrequencyEstimator
creates
a rectangular QAM coarse frequency offset estimator object, H
.
This object uses an openloop, FFTbased technique to estimate the
carrier frequency offset in a received rectangular QAM signal.
H = comm.QAMCoarseFrequencyEstimator(Name,Value)
creates
a rectangular QAM coarse frequency offset estimator object, H
,
with the specified property Name set to the specified Value. You can
specify additional namevalue pair arguments in any order as (Name1,Value1,...,NameN,ValueN).

Desired frequency resolution (Hz) Specify the desired frequency resolution for offset frequency
estimation as a positive, real scalar of data type double. This property
establishes the FFT length that the object uses to perform spectral
analysis. The value for this property must be less than or equal to
half the 

Sample rate (Hz) Specify the sample rate in samples per second as a positive,
real scalar of data type double. The default is 
clone  Create QAMCoarseFrequencyEstimator object
with same property values 
isLocked  Locked status for input attributes and nontunable properties 
release  Allow property value and input characteristics changes 
reset  Reset states of the QAMCoarseFrequencyEstimator object 
step  Estimate frequency offset for QAM signal 
[1] Nakagawa, T., Matsui, M., Kobayashi, T., Ishihara, K., Kudo, R., Mizoguchi, M., and Y. Miyamoto. "Nondataaided widerange frequency offset estimator for QAM optical coherent receivers", Optical Fiber Communication Conference and Exposition (OFC/NFOEC), 2011 and the National Fiber Optic Engineers Conference , March, 2011, pp. 1–3.
[2] Wang, Y., Shi. K., and E. Serpedin. "NonDataAided Feedforward Carrier Frequency Offset Estimators for QAM Constellations: A Nonlinear LeastSquares Approach", EURASIP Journal on Advances in Signal Processing, Vol. 13, 2004, pp. 1993–2001.