User manual - labAlive



Interactive simulation of communication systems

On this site experiments in the field of communications technology are provided online free for use.

Just click the Launch button of any experiment to start the specific simulation. It's a Java application that is launched via Java Web Start.

Each experiment uses a specific simulation that is implemented using labAlive. labAlive is a graphical and interactive simulator tool for communications systems. The virtual experiment environment emulates a real-world laboratory.

Digital
Block diagram as primary GUI provides access to measure instruments and systems.
16-QAM transmitted signal Qam transmission spectrum
16 qam constellation diagram 16-QAM eye pattern diagram
BER Power
Graphical tools emulate real measure instruments: Oscilloscope, including eye diagram, spectrum analyzer, constellation diagram, bit error rate meter, power meter...

Generator Root
System parameters can be adjusted interactively, e.g. frequency of a signal generator, filter cut-off frequency.
Extended Pedestrian
Transfer function and Impulse response can be viewed.
Setup
Configuration can be adapted, e.g. quadrature or baseband modem, OFDM prefix length and pulse shape of a modulator.

Open measures and system properties

Linear Time Invariant System
Block diagram as primary GUI provides access to measure instruments and systems.

Click on wire Open measure

Left click on a wire.

x signal

Open the default measure, usually oscilloscope.

Osci

Right click on a wire.

x signal

Select a measure. The set of offered measures depends

on the signal type of the wire, e.g. analog, digital, complex signal.

Measure selector for analog signals

Click on system Open system properties

Left click on a system box or a bullet

representing a generator.

Generator

Signal

Right click on a system box.

extended pedestrian model block symbol

View the transfer function or impulse response of filters.

View transfer function or impulse response of filters

Measure settings

Click on the settings icon to adjust instrument settings.
Click on settings icon settings Open measure settings
Osci xt
Signal sf

Click on more details button� button Open measure settings details
sf signal Analyzer
Analyzer spectrum

Keys & shortcuts

Key Action
Pause Pause or continue the simulation.
F2 Slow down the simulation speed (50%).
F3 Speed up the simulation speed (200%).
F4 Reset to initial simulation speed.
F5 Process one simulation step and then pause.
F6 Process 10 simulation steps and then pause.
F7 Process 100 simulation steps and then pause.
F8 Show speed slider.
Adjust simulation speed
F9 Show simulation status.
Simulation status
F10 Show preferences dialog.
Preferences dialog
F11 Show simulation settings dialog. (Depends on simulation)
Simulation settings dialog
F12 Show simulation setup dialog. (Depends on simulation)
Simulation setup dialog

Measures overview

With mylabAlive you can simulate so many different hardware experiments that the range of possibilities are up to yourself. You'll need different measures to see or hear what the simulation is doing.

Each measure is designed for a special field. The best thing is, the instruments would cost a lot in reality, but are free in these simulations.


Table 1: Overview of measures
Name Code
Audio Player audioPlayer
Audio Player Stereo audioPlayerStereo
ComplexScope complexScope
Constellation Diagram constellationDiagram
Digital Oscilloscope digitalScope
Multimeter multimeter
Oscilloscope scope
Oscilloscope, ImpulseResponse impulseResponseScope
Powermeter powermeter
Probability Density density
Signal Logging signalLogging
Signal Viewer signalViewer
Spectrumanalyzer spectrum
Spectrumanalyzer, Transferfunction transferFunctionSpectrum
TransmitchainSignalLabels transmitChainSignalLabels
XY Meter xyMeter

Oscilloscope - operate and control

The oscilloscope is one of the most important/significant measuring instrument in electronics. This description is designed to give an overview about the measure.

Open oscilloscope

Depending on the simulation, the oscilloscope opens automatically. Alternating open the scope by right-click on the wire and selecting oscilloscope. Left-click on the wire will open the default measure, which is also usually the oscilloscope.

Mainwindow with measure selector
Picture 1: Right-click on wire to open measure selector

In some simulations the scope will start togehter with the control element. Depending on the experiment, the scope may differ in form of the background, beam and grid. To get more informations about these design settings, please visit the Preferences tab.

Oscillosope screen with sine wave
Picture 2: Oscillosope screen with sine wave

Measure

To measure the amplitude of the signal at a certain time or measure the rising time of a signal to a certain amplitude, mark the signal by clicking at the spot with the left mouse. A fine red-dotted line shows the time and amplitude at the marked spot.

The marked measuringspot will dissappear within the next cycle of the oscilloscope. To prevent this, press Pause on the keyboard to pause the simulation. After the simulation pauses, the measuringspot will stay at the display. To restart the simulation, again press the Pause key.

To delete the marker, double-click with the left mouse on the scope and the marker disappear.

Oscilloscope screen with markers
Picture 3: Marker on signal to measure time and amplitude

Open settings

We discussed how to change the design of the scope. If you want to change the amplitude/ division, time/division or shift the signal you can open the settings menu with 2 options.


First method: Right-click on scope

The menu will popup and display all settings (Picture 4).

Second method: Gear symbol

Click on the gear symbol located in the upper right corner of the scope. The ampl/div and time/div settings appear. With the arrow on the right-side (green circle), you can open further adjustments.

Note: You need to click through 2 more stages to get to the full settings menu.


Overview of all oscilloscope setting stages
Picture 4: All stages of oscilloscope setting

In picture 4 you can see the settings menu. Declaration of every single setting can be found in table 1.

Table 1: Oscilloscope settings
Settings
AMPL / DIV Changes the amplitude per division. Affects the y-axis
TIME / DIV Changes the time per division. Affects the x-axis
Offset Adds a certain offset of the signal. Affects the y-axis
y min Shifts the zero-line horizontally.
y-axis shift Shifts the y-axis vertical.
Draw

Continous

Discrete

Dirac

Sample & hold

Luminiscence

Single beam

Luminiscence

Eye pattern

Display size

Frame - half 441px

Frame - quarter 219px

Frame - full 890px

Diagram - quarter 219px

Diagram - half 441px

Diagram - full 890px

Print - quarter 477px

Print - half 943px

Print - full 1906px

604px

Keep Beam Freezes the the graph

Other Oscilloscopes

Table 2: Overview of different oscilloscopes and corresponding code
Measure Code
ComplexScope complexScope
digital oscilloscope digitalScope
oscilloscope, impulseresponse impulseResponseScope

Spectrum analyzer - operate and control

Next to the oscilloscope(put link in here), the spectrum analyzer is an important instrument in the development of circuits. A spectrum analyzer is a piece of electronic equipment that is used to measure the magnitude of an input signal set against the full frequency range of the instrument. The x axis shows the frequency and on the y axis the amplitude/level.

Open spectrum analyzer

Note, whether the simulation automatically opens the spectrum analyzer, you are able to open the measure by right-click on the wire and selecting Spectrum Analyzer

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Picture 1: Right-click on wire to open measure selector

In some simulations the spectrum analyzer will start togehter with the main window. Depending on the experiment, the display may differ in form of the background, beam and grid. To get more informations about the settings, please visit the Preferences tab.

Timebased signal against frequency based signal
Picture 2: Example of a signal as time function (left) and spectrum (right)

Measure

The spectrum analyzer can be used to measure the amplitude/level at a certain frequency. Mark the frequency with the left mouse button. A fine, red-dotted line shows the frequency and amplitude/level at the marked spot.

To delete the marker, double-click with the left mouse button on the scope. The marker disappear.

Spectrum screen with markers
Picture 3: Marker on the signal to measure the frequency and amplitude/level

Open settings

To change the amplitude/division, time/division or shift the signal open the settings menu with one of the 2 following options.


First method: Right-click on scope

The menu will popup and display all settings (Picture 4).

Second method: Gear symbol

Click on the gear symbol located in the upper right corner of the scope. The ampl/div and time/div settings appear. With the arrow on the right-side (green circle), you can open further adjustments.

Note: You need to click through 2 more stages to get to the full settings menu.


Overview of all spectrum analyzer setting stages
Picture 4: All stages of spectrum analyzer setting

In picture 4 you can see the settings menu. Declaration of every single setting can be found in table 1.

Table 1: Spectrum analyzer settings
Settings
AMPL / DIV Changes the amplitude per division. Affects the x-axis
FREQ / DIV Changes the frequency per division. Affects the y-axis
Resolution Bandwidth
Down Sampling
Start Amplitude Adds/subtracs Divisions
Reference level Sets the reference level
Center Frequency Changes the start frequency (Only TransferFunction Spectrum)
Start Frequency Changes the start frequency
Draw

Continous

Discrete

Dirac

Sample& hold

Spectrum

V(Periodical)

V/Hz(Pulse)

V²/Hz(Power density)

(Transfer Function)

Scale

Linear

Log

Averaging

On

Off

Fourier Transformation

FFT

DFT

DFT two-sided

Windowing

Off

On

Display size

Frame - half 441px

Frame - quarter 219px

Frame - full 890px

Diagram - quarter 219px

Diagram - half 441px

Diagram - full 890px

Print - quarter 477px

Print - half 943px

Print - full 1906px

604px

Keep Beam Freezes the the graph

Other spectrumanalyzer

Table 2: Overview of different spectrumanalyzer and corresponding code
Measure Code
Spectrumanalyzer, transferfunction transferFunctionSpectrum

Small Measures

labAlive provides additional small measures which allows the user to perform a large number of different measurements. Each measure covers a specific field of measurement. This overview is designed to show each measure with an image of the interface, a small introduction and a table with the corresponding code.

To use one of the measure in a simulation, take the code from the corresponding table and paste it into the sourcecode of the simulation.

Multimeter

Multimeter GUI
Picture 1: Power Meter GUI

The multimeter is an electronic measure that combines several measurement functions in one unit. Against the "real" multimeter this one can measure power, average of the signal, PAPR and peak amplitude.

To change the measure function, click on the gear symbol located on the right side of the GUI. Table 1 shows an overview of all functions.


Table 1: Modes of multimeter
Multimeter
Mode Unit Description
Power Normalized electric instantaneous power
Average V Arithmetic mean of the signal
Peak-to-average power ratio dB PAPR is the peak amplitude squared (peak power) divided by the average power
Peak amplitude V Peak amplitude of the signal

The measure can be called in the source code of the simulation. To include this, please consider to take the code out of table 2.

Table 2: Overview of measure and corresponding code
System Code
Multimeter multimeter

Power Meter

Power Meter GUI
Picture 2: Power Meter GUI

A power meter ist a electronic measure that measures the amount of electric energy. In this case, the power meter measures the energy of signals in V². This is the only measurement function.

The measure can be called in the source code of the simulation. To include this, please consider to take the code out of table 3


Table 3: Overview of measure and corresponding code
System Code
Power Meter powerMeter

Signal viewer

Signal viewer GUI
Picture 3: Signal viewer GUI

The signal viewer is a tool which allows the user to see the current value of the signal. This device measures voltages in V and prints the value in a decimal number.

The signal viewer prints the value on the screen. The values can be logged with the signal logging tool.

These measures can be called in the source code of the simulation. To include this, please consider to take the code out of table 4.


Table 4: Overview of measure and corresponding code
System Code
Signal viewer signalViewer
Signal logging signalLogging

Audio player

Audio player GUI
Picture 4: Audio player GUI
Table 5: Overview of measure and corresponding code

The audio player can be used to play the signal like an audio wave.

These measures can be called in the source code of the simulation. To include this, please consider to take the code out of table 5.


System Code
Audio player audioPlayer
Audio Player Stereo audioPlayerStereo

Constellation diagram

Picture 5: Constellation diagram GUI

A constellation diagram displays the signal as a two-dimensional xy-diagram. The angle of each point represents the phase shift of the carrier wave. Most times this tool is used together with QPSK and PSK applications.

The measure can be called in the source code of the simulation. To include this, please consider to take the code out of table 6.


Table 6: Overview of measure and corresponding code
System Code
Constellation diagram constellationDiagram