Coarse Frequency Compensator
Compensate for carrier frequency offset for PAM, PSK, or QAM
Library
Synchronization
Description
The Coarse Frequency Compensator block compensates for a carrier frequency offset for BPSK, QPSK, OQPSK, 8PSK, PAM, and QAM modulation schemes. The block accepts a single input signal. To obtain an estimate of the frequency offset in Hz, select the Estimated frequency offset output port check box. The block accepts a sample or framebased complex input signal and returns a complex output signal and a real frequency offset estimate. The output signal has the same dimensions as the input signal. The frequency offset estimate is a scalar.
Parameters
 Modulation type of input signal
Specify the modulation type as
BPSK
,QPSK
,OQPSK
,8PSK
,PAM
, orQAM
.The default setting is
QAM
. Estimation algorithm
Specify the frequency offset estimation algorithm as
FFTbased
orCorrelationbased
. This parameter appears when Modulation type of input signal isBPSK
,QPSK
,8PSK
, orPAM
.The table shows the allowable combinations of the modulation type and the estimation algorithm.
Modulation FFTBased Algorithm CorrelationBased Algorithm BPSK
,QPSK
,8PSK
,PAM
✓ ✓ OQPSK
,QAM
✓  Frequency resolution (Hz)
Specify the frequency resolution in Hz as a positive real scalar. This option is available when the
FFTbased
algorithm is used. The default setting is0.001
Hz. Samples per symbol
Specify the number of samples per symbol as a positive integer scalar greater than or equal to 4. The default setting is 4.
 Maximum frequency offset (Hz)
Specify the maximum frequency offset in Hz as a positive real scalar. This option is appears when you set Estimation algorithm to
Correlationbased
. The default setting is0.05
Hz. Estimated frequency offset output port
Select this check box to provide the estimated frequency offset to an output port. The default for this parameter is selected.
 Simulate using
Select the simulation mode.
Code generation
On the first model run, simulate and generate code for the block using only MATLAB^{®} functions supported for code generation. If the structure of the block does not change, subsequent model runs do not regenerate the code.
If the simulation mode is
Code generation
, System objects accept a maximum of nine inputs.Interpreted execution
Simulate your model using all supported MATLAB functions. Choosing this option can slow simulation performance.
The default setting is
Code generation
.
Algorithms
This block implements the algorithm, inputs, and outputs described on the comm.CoarseFrequencyCompensator
reference page. The object properties
correspond to the block parameters.
Examples
Supported Data Types
Port  Supported Data Types 

Signal Input 

Signal Output 

Frequency Estimate 

References
[1] Luise, M. and R. Regiannini. “Carrier recovery in alldigital modems for burstmode transmissions.” IEEE^{®} Transactions on Communications.Vol. 43, No. 2, 3, 4, Feb/Mar/April, 1995, pp. 1169–1178.
[2] Wang, Y., K. Shi, and E. Serpedi. “NonDataAided Feedforward Carrier Frequency Offset Estimators for QAM Constellations: A Nonlinear LeastSquares Approach.” EURASIP Journal on Applied Signal Processing. 2004:13, pp. 1993–2001.
[3] Nakagawa, T., M. Matsui, T. Kobayashi, K. Ishihara, R. Kudo, M. Mizoguchi, 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.