Designing Virtual Practicum Modules for Basic Laboratory of

Telecommunication System

Maksum Pinem*, Muhammad Zulfin, Naemah Mubarakah, Sri Indah Rezkika

Electrical Engineering Department, Universitas Sumatera Utara, Padang Bulan, 20155 Medan, Indonesia

Keywords: Basic Telecommunications, Modeling, Simulation, GUI, Matlab.

Abstract : Accordance with the development of information technology in the form of network technology and software,

then as a companion physical laboratory proposed a powerfull innovation in the form of innovation laboratory

designing and implementing software-based telecommunication system (virtual laboratory).The Virtual

Laboratory presents a number of advantages such as portability, ease of re-deployment processes, to lower

cost of provision and operation.This paper designs and builds a virtual laboratory of telecommunication

systems based on the procurement of virtual individual practical work modules which then integrate between

the modules. Based on the results of the tests conducted, has been obtained and has successfully executed

seven modules of virtual practicum that is integrated and ready to be empowered for student practicum.

1 INTRODUCTION

Procurement of laboratory infrastructure is a part that

often becomes a major obstacle for universities to

produce qualified graduates.One of the challenges

faced by the laboratory is the limitations of physical

practicum modules and measuring instruments.But

there are two solutions offered to overcome the

problem that is by making the device itself as

practicum practiced by (Darlis, A. R, 2013;

Kharisma, W., A., 2013; Supriandani, Y, 2015) the

second solution is to make a breakthrough media

development as a supplement learning teaching

materials lab that so far can be done with two

approaches, namely Augmented Reality or ARLAB

and Virtual Laboratory or commonly referred to as

VLAB. However, the creation of instructional media

should be in accordance with educational standards

and may represent actual practicum (Potkonjak,

2016), so it can be used by learners who have limited

access to laboratory equipment, because basically the

learning media is one model approach to help know,

understand and analyze certain phenomena contained

in a field of science. In addition, one of the principles

of learning media is not limited to use at anytime and

anywhere by anyone who wants to operate.

Virtual laboratory is one form of modern

laboratory that is enough to help institutions,

educators or learners in the implementation of

practice-based learning. The results of a research

survey of students using physical and virtual labs

show that virtual labs are better in terms of physical

security availability (Burd. Stephen D, 2009).

Of course, the development of virtual laboratories

is inseparable from reliable Software support that

integrates computing, visualization and programming

in an easy-to-use environment where problems and

solutions are expressed in familiar mathematical

notation. In the field of engineering, especially

Telecommunication Engineering, the utilization of

GUI-based simulation software such as Matlab which

provides convenience in explaining scientific

concepts when quite a lot of mathematical terms are

involved in the teaching process (Mohamed S. Al

Oraibi, 2016; Shalini Garg, 2014). Therefore, this

research designs and builds a virtual laboratory of

telecommunication systems based on the

procurement of virtual individual practicative

modules which then is done to integrate all the

individual practice modules.

248

Pinem, M., Zulﬁn, M., Mubarakah, N. and Rezkika, S.

Designing Virtual Practicum Modules for Basic Laboratory of Telecommunication System.

DOI: 10.5220/0010080602480253

In Proceedings of the International Conference of Science, Technology, Engineering, Environmental and Ramiﬁcation Researches (ICOSTEERR 2018) - Research in Industry 4.0, pages

248-253

ISBN: 978-989-758-449-7

2 METHOD

The method used in this study is a simulation method

based on computer programming design with GUI-

based Matlab Software (Averill M. Law, 2000; Math

Works., Inc., 2015). The model of the design system

is shown in Figure 1.

Figure 1: Design system model

The steps taken in the design of a virtual

laboratory based telecommunication software system

are as follows:

1. Collecting the need for practicum materials and

literature studies. The seven practical subjects of

the telecommunication system are:

a. Practicum generating oscillator signal by Hartley

method

b. Practicum generation of oscillator signal with

Colpitts method.

c. Practicum of low pass filter characteristics

d. Practicum characteristic of high pass filter

e. Practicum modulator analog amplitude

f. Analog to digital conversion practice (ADC)

g. Digital to analog conversion practice (DAC)

2. Designing individual Practicum Modules

Detailed virtual lab material practicum designed in

Matlab GUI form, RF Oscillator consisting of Colpitt

Oscillator and Oscillator, AM DSB-FC Modulator,

Signal converter consisting of ADC

and DAC signal

converter, and active filter consisting of low pass

filters and high pass filters. The steps in designing the

individual GUI of the entire virtual lab material are

generally outlined as follows:

a. Open the GUI worksheet.

b. Create a figure design using panel components,

slider components, static text, and axes

components into the GUI whose number of needs

is adjusted to each material.

c. Edit the properties of each component by double-

clicking each component then changing its

property as needed. Through property inspector,

each component can be customized starting from

background color, font type, font size, tag and

string.

d. Save a figure by clicking CTRL + S on the

keyboard or by pressing the save button on the

Matlab worksheet.

e. After finished designing the figure, the next step

is to save the figure will automatically be created

m-file frame with the same name.

f. Add a script or program so that the control

components can work.

g. Run the GUI by clicking the runner button on the

tool strip and will produce a view like the saved

image.

3. Designing GUI Module Multitab Integration.

Program Design Multitab GUI Matlab consists of

several files and folders, namely app, contents,

themes, index.m, as shown in Figure 2.

Figure 2: Multitab Folder GUI Matlab

Here is an explanation of the GUI multitab file

and program folder:

1. app, which is a folder that contains a set sintax

m-file that serves to arrange the entire tab in the

integrated GUI.

2. contents, that is, the folders containing the

individual GUI sets that will be displayed on the

integrated GUI tabs.

3. themes, namely the folder containing the theme

to change the display theme of multitab GUI

application.

4. index, the m-file that serves to call the app to run

multitab GUI application Matlab.

The first thing the program does is get the directory

names in the contents directory. There all the contents

of the tabs you want to display in the main GUI are

stored. The code for obtaining the names of the

existing directories is CONTENTS =

Designing Virtual Practicum Modules for Basic Laboratory of Telecommunication System

249

DIR(ARG.CONTENTSDIR). Then the number of

existing directories is stored inside the contentCount

variable. This number is subtracted by two because

the directory directory "." And the directory ".."

which is the navigation directory are also counted.

Then from the directory names obtained looping

operations to open the file figures in each directory

and retrieve data from the figure and move it to the

main GUI data. A button will then be created on the

main GUI to access this figure data from the main

GUI. As long as each loop of the configuration file in

each directory is also read and applied to the tab in

question. The existing configuration is the tab key

title that will be displayed on the main GUI as well as

the name of the documentation for the tab in question.

Figure 3: Flowchart Main GUI Reading Process

For a clearer picture, the process of reading each

figure of a directory into tabs in the main GUI can be

seen in the flowchart in Figure 3.

To add a tab from the contents folder, by creating

a new GUI project or using an existing GUI project,

save the project in the [PROJECT_NAME] folder

with the naming [PROJECT_NAME] _contentview,

so after the save two files will be obtained:

[PROJECT_NAME] _contentview.fig and

[PROJECT_NAME] _contentview.m. If using an

existing project, save as project with the file name in

accordance with the same provisions. Then create the

"config.txt" file in the "contents /

[PROJECT_NAME]" folder, then save it and exit it.

To remove or reduce unwanted GUIs, simply delete

the previously created project folder.

3 RESULT AND DISCUSSION

To run the Integrated GUI Virtual Lab is as follows:

a. In the GUI mutitab program folder, click "index"

twice. Then click the runner button, or

b. In the GUI mutitab program folder, type "index"

in the command window, so it will show at

Figure 4.

Figure 4: Multitab Main GUI Display

3.1 Testing of RF Oscillator GUI

The steps to run the RF Oscillator GUI are as follows:

1. In the integrated GUI, select or click the

"oscillator" tab, then it will be directed to the

overview tab page.

2. Select the "RF Oscillator" tab. GUI

Oscillator RF which consists of Hartley

Osilator and Colpitt Oscillator.

3.1.1 Hartley Oscillator

The steps to run it are as follows:

1. Set the value of L1 and L2 to determine the value

of inductor 1 and inductor 2

2. Set the C value to determine the value of the

capacitor

3. Set the value of A to determine the signal

amplitude value, so it will produce as in Figure

ICOSTEERR 2018 - International Conference of Science, Technology, Engineering, Environmental and Ramiﬁcation Researches

250

Figure 5: Test Result of GUI Oscillator Hartley

3.1.2 Colpitt Oscillator

The steps to run it are as follows:

1. Set the value of C1and C2 to determine the value

of inductor 1 and inductor 2

2. Set the value L to determine the value of the

capacitor

3. Set the value A to determine the signal amplitude

value, so it will produce a display like Figure 6.

Figure 6: Test Result of GUI Oscillator

3.2 Testing of AM Modulator GUI

The step to run it are as follow:

1. In the integerated GUI, select or click the

“modulator” tab, then it will be

2. Select the “AM Modulator”

3. Set the amplitude value of the information signal

4. Set the frequency value of the information signal

5. Set the amplitude value of the carrier signal

6. Set the carrier signal frequency value

7. Set the modulation index value

Figure 7 shows the test results obtained with a

maximum frequency of 5 Hz information signal

input, the input signal information amplitude of 0.3

V, the carrier signal input frequency is 30 Hz, the

amplitude of the input signal 0.2 V with the

modulation index 1.

Figure 7: Test Result GUI AM Modulator

3.3 Testing of Signal Converter GUI

The steps to run GUI Converter Signals are as

follows:

1. In the integrated GUI, select or click the

“converter” tab, then it will be directed to the

overview page.

2. Select the “AD & DA Converter” tab. This AD

& DA Converter Tab consists of GUI Converter

of ADC and DAC signals merged into one tab.

3.3.1 DC Signal Converter

Converter A / D or ADC converts analog

measurements from 0.00 V up to 5.00 V into digital

measurements with 8-bit resolution. Figure 8 shows

the conversion result of analog voltage 1.115 V. Then

obtained the quantization value 1.12125. From the

quantization value then obtained the code number 57

and converted into binary form to 0011 1001 and

shows the pulse form in NRZ format.

Figure 8: Test Result of GUI Converter Signal

3.3.2 DAC Signal Converter

In Figure 9 we can see the example of D / A signal

Converter testing. The digital or binary input is

11001011 .This value is then converted to a decimal

number to obtain the code number 203 .From the

value of the number code then obtained the

quantization value of 3.9682.Of the previous values

then obtained value for the analog output current of

0.8435 A and an output voltage analog of 3.9648 V.

Designing Virtual Practicum Modules for Basic Laboratory of Telecommunication System

251

Figure 9: Result of GUI DAC Signal Converter

3.4 GUI Testing Active Filter Low Pass

Second Order

The steps to run the Active Pass Second Order Low

Pass GUI are as follows:

1. In the integrated GUI, select or click the " filter "

tab , then it will be directed to the overview page

2. Select the "Low Pass Filter" tab

3. Set Vin value set at 0.7 V, R1 50 Ohm, R2 200

Ohm, R3 450 Ohm, R4 900 Ohm, C1 0.03 μF,

C2 0.08 μF, and Fin 1000 Hz , then the result are

obtained, ie the cut-off frequency of 5104.9 Hz,

V out at 3.43472 V dan Gain (dB) at 13.8159 dB,

so it will display the results in Figure 10.

Figure 10: Test Result of Low Pass Active Filter

3.5 GUI Testing High Pass Active

Filter Second Order

The steps for running the Second Order High Pass

Active GUI Filter are as follows:

1. In the integrated GUI, select or click the "filter"

tab, then it will be directed to the overview

page.

2. Select the "High Pass Filter" tab

3. Set Vin value to determine input voltage value

4. Set the value of R1 to determine the value of

resistance 1

5. Set the value of R2 to determine the value of

resistance 2

6. Set the value of R3 to determine the value of

resistance 3

7. Set the value of R4 to determine the value of

resistance 4

8. Set the value of C1 to determine the value of

capacitor 1

9. Set the value of C2 to determine the value of

capacitor 2

10. Set the F

value to specify the input frequency

value.

By adjusting V

1 V, R1 40 Ohm, R2 400 Ohm, R3

2100 Ohm, R4 750 Ohm, C1 0,31 μF, C2 0,85 μF,

and F

1000 Hz. Results obtained, ie cut-off

frequency of 2451.15 Hz, V

out

of 4.1552 V and Gain

(dB) of 12.3718 dB obtained from the logarithm of

the ratio between V

out

and V

. Test results can be

seen in Figure 11.

Figure 11: Result of High Pass Active Filter

4 CONCLUSIONS

Based on the results of the tests conducted, has been

obtained and has successfully executed seven

modules of virtual practicum that is integrated and

ready to be empowered for student practicum. The

innovative design and implementation activities of

the laboratory. The software - based

telecommunication system has supported a collegiate

strategy plan to prepare a superior learning system

that empowers information technology systems and

builds recognition and reputation.

ACKNOWLEDGMENT

The work of this research is supported by DRPM

kemenristekdikti of applied research scheme for

budget year 2018. No. :192/UN5.2.3.1./PPM/KP-

DPRM/2018.

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252

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