constellation
Calculate or plot ideal signal constellation
Description
Examples
Plot QPSK Reference Constellation
Create a QPSK modulator.
mod = comm.QPSKModulator;
Determine the reference constellation points.
refC = constellation(mod)
refC = 4×1 complex
0.7071 + 0.7071i
-0.7071 + 0.7071i
-0.7071 - 0.7071i
0.7071 - 0.7071i
Plot the constellation.
constellation(mod)
Reconfigure the object for bit input and plot the constellation to show the binary values of the Gray-encoded mapping.
release(mod) mod.BitInput = true; constellation(mod)
Create a QPSK demodulator having phase offset set to 0
.
demod = comm.QPSKDemodulator(0);
Plot the reference constellation. The constellation
method works for both modulator and demodulator objects.
constellation(demod)
Plot PSK Reference Constellation
Create a PSK modulator.
mod = comm.PSKModulator;
Determine the reference constellation points.
refC = constellation(mod)
refC = 8×1 complex
0.9239 + 0.3827i
0.3827 + 0.9239i
-0.3827 + 0.9239i
-0.9239 + 0.3827i
-0.9239 - 0.3827i
-0.3827 - 0.9239i
0.3827 - 0.9239i
0.9239 - 0.3827i
Plot the constellation.
constellation(mod)
Create a PSK demodulator having modulation order 16.
demod = comm.PSKDemodulator(16);
Plot its reference constellation. The constellation
method works for both modulator and demodulator objects.
constellation(demod)
Plot BPSK Reference Constellation
Create a BPSK modulator.
mod = comm.BPSKModulator;
Determine the reference constellation points.
refC = constellation(mod)
refC = 2×1 complex
1.0000 + 0.0000i
-1.0000 + 0.0000i
Plot the constellation.
constellation(mod)
Create a BPSK demodulator having phase offset set to .
demod = comm.BPSKDemodulator(pi/2);
Determine the reference constellation points.
refC = constellation(demod)
refC = 2×1 complex
0.0000 + 1.0000i
-0.0000 - 1.0000i
Plot the reference constellation. The constellation
method works for both modulator and demodulator objects.
constellation(demod)
Plot OQPSK Reference Constellation
Create a OQPSK modulator.
mod = comm.OQPSKModulator;
Determine the reference constellation points. The constellation that displays does not depict the IQ delay introduced by the OQPSK modulator.
refC = constellation(mod)
refC = 4×1 complex
0.7071 + 0.7071i
-0.7071 + 0.7071i
-0.7071 - 0.7071i
0.7071 - 0.7071i
Plot the constellation.
constellation(mod)
Change the phase offset for the modulated symbols. Plot the constellation to show the rotated constellation points.
release(mod) mod.PhaseOffset = 45*pi/180; constellation(mod)
Calculate Ideal PAM Signal Constellation
Create comm.PAMModulator
and comm.PAMDemodulator
System objects, and then calculate their ideal signal constellations.
Create modulator and demodulator objects.
mod = comm.PAMModulator; demod = comm.PAMModulator;
Calculate the constellation points.
refMod = constellation(mod)
refMod = 4×1
-3
-1
1
3
refDemod = constellation(demod)
refDemod = 4×1
-3
-1
1
3
Verify that both objects produce the same points.
isequal(refMod,refDemod)
ans = logical
1
Display the ideal signal constellation.
constellation(mod)
Input Arguments
obj
— System object™ to return constellation for
System object
System object to return constellation for, specified as a modulator System object.
Data Types: object
Output Arguments
symbols
— Constellation points
complex vector (default)
Constellation points, returned as a complex vector.
Data Types: double
| single
Complex Number Support: Yes
Version History
Introduced in R2012a
MATLAB Command
You clicked a link that corresponds to this MATLAB command:
Run the command by entering it in the MATLAB Command Window. Web browsers do not support MATLAB commands.
Select a Web Site
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
You can also select a web site from the following list:
How to Get Best Site Performance
Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.
Americas
- América Latina (Español)
- Canada (English)
- United States (English)
Europe
- Belgium (English)
- Denmark (English)
- Deutschland (Deutsch)
- España (Español)
- Finland (English)
- France (Français)
- Ireland (English)
- Italia (Italiano)
- Luxembourg (English)
- Netherlands (English)
- Norway (English)
- Österreich (Deutsch)
- Portugal (English)
- Sweden (English)
- Switzerland
- United Kingdom (English)