genqammod

General quadrature amplitude modulation (QAM)

collapse all in page

Syntax

y = genqammod(x,const)

Description

example

y = genqammod(x,const) returns the complex envelop of the QAM for message signal x. Input const specifies the signal mapping for the modulation.

Examples

collapse all

Open Live Script

Create the points that describe a hexagonal constellation.

inphase = [1/2 1 1 1/2 1/2 2 2 5/2];
quadr = [0 1 -1 2 -2 1 -1 0];
inphase = [inphase;-inphase]; inphase = inphase(:);
quadr = [quadr;quadr]; quadr = quadr(:);
const = inphase + 1i*quadr;

Plot the constellation.

h = scatterplot(const);

Generate input data symbols. Modulate the symbols using this constellation.

x = [3 8 5 10 7];
y = genqammod(x,const);

Demodulate the modulated signal, y.

z = genqamdemod(y,const);

Plot the modulated signal in same figure.

hold on;
scatterplot(y,1,0,'ro',h);
legend('Constellation','Modulated signal');

Determine the number of symbol errors between the demodulated data to the original sequence.

numErrs = symerr(x,z)
numErrs = 0

Input Arguments

collapse all

Message signal, specified as a scalar, vector, matrix, or 3-D array of numeric values. The message signal must consist of integers from 0 and length(const)–1. If x is a matrix with multiple rows, the function processes the columns independently.

Data Types: double | single | fi | int8 | int16 | uint8 | uint16

Signal mapping, specified as a complex vector.

Data Types: double | single | fi | int8 | int16 | uint8 | uint16
Complex Number Support: Yes

Output Arguments

collapse all

Complex envelope, returned as a scalar, vector, matrix, or 3-D array of numeric values. The length of y is the same as the length of input x.

Data Types: double | single | fi | int8 | int16 | uint8 | uint16

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

See Also

| | | |

Topics

Introduced before R2006a

Communications Toolbox Documentation

Support