Measurements, Visualization, and Analysis

Graphical and quantitative analysis

Communications Toolbox™ provides quantitative tools for measuring system performance. Use graphical utilities such as constellation and eye diagrams to visualize the effects of various impairments and corrections.

Apps

Wireless Waveform Generator	Create, impair, visualize, and export modulated waveforms
BER Analyzer	Analyze bit error rate (BER) performance of communications systems

Functions

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Bit Error Rate Calculation and Estimation

`biterr`	Number of bit errors and bit error rate (BER)
`symerr`	Compute number of symbol errors and symbol error rate
`berawgn`	Bit error rate (BER) for uncoded AWGN channels
`bercoding`	Bit error rate (BER) for coded AWGN channels
`berconfint`	Bit error rate (BER) and confidence interval of Monte Carlo simulation
`berfading`	Bit error rate (BER) for Rayleigh and Rician fading channels
`berfit`	Fit curve to nonsmooth empirical bit error rate (BER) data
`bersync`	Bit error rate (BER) for imperfect synchronization
`semianalytic`	Calculate bit error rate (BER) using semianalytic technique

Visualization

`scatterplot`	Generate scatter plot
`eyediagram`	Generate eye diagram
`plotPhaseNoiseFilter`	Plot response of phase noise filter block

Utilities

`marcumq`	Generalized Marcum Q function
`noisebw`	Equivalent noise bandwidth of filter
`qfunc`	Q function
`qfuncinv`	Inverse Q function
`showcommblockdatatypetable`	Communications Toolbox block characteristics

Objects

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Measurements

`comm.ACPR`	Adjacent Channel Power Ratio measurements
`comm.CCDF`	Measure complementary cumulative distribution function
`comm.ErrorRate`	Compute bit or symbol error rate of input data
`comm.EVM`	Measure error vector magnitude
`comm.MER`	Measure modulation error ratio

Visualization

`comm.ConstellationDiagram`	Display constellation diagram for input signals
`comm.EyeDiagram`	Display eye diagram of time-domain signals
`dsp.SpectrumAnalyzer`	Display frequency spectrum of time-domain signals
`dsp.TimeScope`	Time domain signal display and measurement
`dsp.ArrayPlot`	Display vectors or arrays

Blocks

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Measurements

Error Rate Calculation	Compute bit error rate or symbol error rate of input data
EVM Measurement	Measure error vector magnitude
MER Measurement	Measure signal-to-noise ratio (SNR) in digital modulation applications

Visualization

Constellation Diagram	Display constellation diagram for input signals
Eye Diagram	Display eye diagram of time-domain signal
Time Scope	Display and analyze signals generated during simulation and log signal data to MATLAB
Spectrum Analyzer	Display frequency spectrum

Topics

Bit Error Rate (BER)

Obtain numerical evaluation results.

Adjacent Channel Power Ratio (ACPR)

Adjacent channel power ratio (ACPR) calculations (also known as adjacent channel leakage ratio (ACLR)), characterize spectral regrowth in a communications system component, such as a modulator or an analog front end.

Error Vector Magnitude (EVM)

EVM Measurements.

Scatter Plots and Constellation Diagrams

Generating scatter plots.

Visualize RF Impairments

Apply various RF impairments to a QAM signal.

Plot Signal Constellations

This example shows how to plot a PSK constellation having 16 points.

Selected Bibliography for Measurements

List of references for further reading.

Featured Examples

Modulation Classification with Deep Learning

Use a convolutional neural network (CNN) for modulation classification. You generate synthetic, channel-impaired waveforms. Using the generated waveforms as training data, you train a CNN for modulation classification. You then test the CNN with software-defined radio (SDR) hardware and over-the-air signals.

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Link Budget Analysis

In the design of wireless communications links between two sites, issues of range, throughput, and received signal quality are of critical importance to the system engineer. Link budget analysis accounts for all gains and losses in the communication link. Some factors and design choices, such as propagation path length, signal polarization, and antenna feed cable, degrade signal quality, while others, such as the power amplifier and antenna size, can increase transmitted signal strength.

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Eye and Constellation Diagram

Use comm.EyeDiagram and comm.ConstellationDiagram in analyzing communication systems.

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Eye Diagram Measurements

Use the comm.EyeDiagram System object™ to perform eye diagram measurements on simulated signals.

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EVM Measurements for a 802.15.4 (ZigBee®) System

Use the comm.EVM System object™ to measure the error vector magnitude (EVM) of a simulated IEEE® 802.15.4 [ 1 ] transmitter. IEEE 802.15.4 is the basis for the ZigBee specifications.

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BLE Blocking, Intermodulation and Carrier to Interference Performance Tests

Model Bluetooth® low energy (BLE) RF-PHY receiver tests specific to blocking, intermodulation and carrier to interference (C/I) performance as per the Bluetooth RF-PHY Test Specifications [ 1 ] using Communications Toolbox™ Library for the Bluetooth Protocol.

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