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pskmod

Phase shift keying modulation

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Syntax

y = pskmod(x,M)
y = pskmod(x,M,ini_phase)
y = pskmod(x,M,ini_phase,symorder)

Description

y= pskmod(x,M)modulates the input signal,x, using phase shift keying (PSK) with modulation orderM.

example

y= pskmod(x,M,ini_phase)specifies the initial phase of the PSK-modulated signal.

y= pskmod(x,M,ini_phase,symorder)specifies the symbol order of the PSK-modulated signal.

Examples

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Open Live Script

Modulate and plot the constellations of QPSK and 16-PSK signals.

QPSK

Set the modulation order to 4.

M = 4;

Generate random data symbols.

data = randi([0 M-1],1000,1);

Modulate the data symbols.

txSig = pskmod(data,M,pi/M);

Pass the signal through white noise and plot its constellation.

rxSig = awgn(txSig,20); scatterplot(rxSig)

图散点图包含an axes object. The axes object with title Scatter plot contains an object of type line. This object represents Channel 1.

16-PSK

Change the modulation order from 4 to 16.

M = 16;

Generate random data symbols.

data = randi([0 M-1],1000,1);

Modulate the data symbols.

txSig = pskmod(data,M,pi/M);

Pass the signal through white noise and plot its constellation.

rxSig = awgn(txSig,20); scatterplot(rxSig)

图散点图包含an axes object. The axes object with title Scatter plot contains an object of type line. This object represents Channel 1.

Open Live Script

Generate random symbols.

dataIn = randi([0 3],1000,1);

QPSK modulate the data.

txSig = pskmod(dataIn,4,pi/4);

Pass the signal through an AWGN channel.

rxSig = awgn(txSig,10);

Demodulate the received signal and compute the number of symbol errors.

dataOut = pskdemod(rxSig,4,pi/4); numErrs = symerr(dataIn,dataOut)
numErrs = 2
Open Live Script

Plot PSK symbol mapping for Gray and natural binary encoded data.

Set the modulation order, and then create a data sequence containing a complete set of constellation points.

M = 8; data = (0:M-1); phz = 0;

Modulate and demodulate the data using Gray and natural binary encoded data.

symgray = pskmod(data,M,phz,'gray'); mapgray = pskdemod(symgray,M,phz,'gray'); symbin = pskmod(data,M,phz,'bin'); mapbin = pskdemod(symbin,M,phz,'bin');

Plot the constellation points using one of the symbol sets. For each constellation point, assign a label indicating the Gray and natural binary values for each symbol.

  • For Gray binary symbol mapping, adjacent constellation points differ by a single binary bit and are not numerically sequential.

  • For natural binary symbol mapping, adjacent constellation points follow the natural binary encoding and are sequential.

scatterplot(symgray,1,0,'b*');fork = 1:M text(real(symgray(k))-0.2,imag(symgray(k))+.15,...dec2base(mapgray(k),2,4)); text(real(symgray(k))-0.2,imag(symgray(k))+.3,...num2str(mapgray(k))); text(real(symbin(k))-0.2,imag(symbin(k))-.15,...dec2base(mapbin(k),2,4),'Color',[1 0 0]); text(real(symbin(k))-0.2,imag(symbin(k))-.3,...num2str(mapbin(k)),'Color',[1 0 0]);endaxis([-2 2 -2 2])

图散点图包含an axes object. The axes object with title Scatter plot contains 33 objects of type line, text. This object represents Channel 1.

Input Arguments

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输入信号,specified as a vector or matrix of positive integers. The elements ofxmust have values in the range of [0,M– 1].

Example:randi([0 3],100,1)

Data Types:double

Modulation order, specified as an integer power of two.

Example:2|4|16

Data Types:double

Initial phase of the PSK modulation, specified in radians as a real scalar.

If you specifyini_phaseas empty, thenpskmoduses an initial phase of 0.

Example:pi/4

Data Types:double

Symbol order, specified as'bin'or'gray'. This argument specifies how the function assigns binary vectors to corresponding integers.

  • Ifsymorderis'bin', the function uses a natural binary-coded ordering.

  • Ifsymorderis'gray', the function uses a Gray-coded ordering.

Data Types:char

Output Arguments

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Complex baseband representation of a PSK-modulated signal, returned as vector or matrix of complex values. The columns ofyrepresent independent channels.

See Also

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Topics

Introduced before R2006a

Communications Toolbox Documentation

万博1manbetx

Bridging Wireless Communications Design and Testing with MATLAB

Bridging Wireless Communications Design and Testing with MATLAB

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