Yuli Christyono
Departemen Teknik Elektro, Universitas Diponegoro Semarang Jl. Prof. Sudharto, SH, Kampus UNDIP Tembalang, Semarang 50275, Indonesia

Published : 50 Documents
Articles

SIMULASI TEKNIK POWER CONTROL DAN MULTI USER DETECTION PADA SISTEM KOMUNIKASI DS-CDMA Christyono, Yuli
TEKNIK Volume 31, Nomor 1, Tahun 2010
Publisher : Fakultas Teknik, Universitas Diponegoro

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Abstract

CDMA is interference limited multiple access system. Because all users transmit on the same frequency,internal interference generated by the system is the most significant factor in determining system capacity andcall quality. The transmit power for each user must be reduced to limit interference, however, the power shouldbe enough to maintain the required Eb/No (signal to noise ratio) for a satisfactory call quality. Maximumcapacity is achieved when Eb/No of every user is at the minimum level needed for the acceptable channelperformance. As the MS moves around, the RF environment continuously changes due to fast and slow fading,external interference, shadowing , and other factors. The aim of the dynamic power control is to limittransmitted power on both the links while maintaining link quality under all conditions. Additional advantagesare longer mobile battery life and longer life span of BTS power amplifiers.In this research will be made a sumulation of power control and multi user detection to avoid the interferencebetween MS.Observations show that the increasing number of users will decrease the value of Signal to Interfrence Ratio(SIR) / SIR below the target. To cope the growing number of users increases can be done by iteration / updatingpower transmit so the convergence computation can be reached and target value SIR can be achieved. Inaddition, to reduce interference can also be done by extending the number of chips.
PERANCANGAN ANTENA 5/8λ BERPOLARISASI CIRCULAR PADA BAND VHF (30-300 MHz) Christyono, Yuli; Santoso, Imam; Setiawan, Budi
TRANSMISI Vol 11, No 1 (2009): TRANSMISI
Publisher : TRANSMISI

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Abstract

Since Hertz and Marconi, antennas have became increasingly important to our society until now they are indispensable. They are everywhere: at home and workplaces, on cars and aircraft, also in ships and satellites. So far most used antenna is an antenna with a single polarization, the horizontal polarization or vertical polarization only. The advantage of circular polarization is the radiation of antenna can be well received by the vertical receiving antenna or horizontal receiving antenna. The purpose of this research is to design and build a circular polarized antenna. Then the values of the parameters measured using Hewlett Packard 8656B Signal Generator as a transmitter and Hewlett Packard 8901A Modulation Analyzer as a receiver. Both measuring devices were used to determine the frequency and power generated by the antenna. SX-1000 SWR meter as a measuring VSWR and analog VU meters are used to determine the signal strength of the antenna. The result shows that the antenna works well on a predetermined frequency (144 MHz), has omni directional radiation pattern and its VSWR is 1.09. The result of the antenna radiation can also be well received, using vertical and horizontal polarization antenna. VU meter shows that the highest value when antenna used as transmitter is 10 μV and 11 μV when antenna is used as receiver antenna. Keywords: Antenna, vertical polarization, horizontal polarization, circular polarization.
Analisis Perpindahan Kanal Komunikasi dalam Satu BSC pada Sistem GSM Berdasarkan Data Drive Test Menggunakan TEMS Investigation 4.1.1 Chalida, Luluk Arifatul; Santoso, Imam; Christyono, Yuli
TRANSMISI Vol 11, No 4 (2009): TRANSMISI
Publisher : TRANSMISI

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Abstract

Mobile communications system created to meet the communication needs that can be done anywhere either when user is motionless or moving. To maintain the quality of services in a wide service area, coverage area is divided into smallest geographic units called cells. If the user moves from one area of the cell to another, then it needs an algorithm that guarantees the continuity of communications services. These algorithm is called a handover to a dedicated mode and the cell reselection for idle mode. In observing handoff algorithm, the operator did a drive test using computer and handset, which each had been equipped with special software, and GPS. This research analyze the problems related to the handoff algorithm, both when in idle mode or dedicated mode, including the causes, processes and things that influence it. Data acquisition is carried out through a drive test using software TEMS Investigaions GSM 4.1.1 with routes in the downtown area of Semarang. Drive test held on every Thursday and Sunday for three consecutive weeks starting on August 23, 2009 and each of day divided into three time allocation, ie morning, noon and night. The observed event include: cell reselection, handover, handover (intracell), handover failure and intracell handover failure. In addition Information Element that effected on the event are also observed, path loss criteria and cell reselection criteria for cell reselection, and received power, bit error rate and timing advance for the four other events. From the analysis is known that the assignment channel is triggered by the Information Element value that reaches a certain threshold value. For cell reselection, the both Information Element having equal influence. Information Element of the most influential for the handover and the handover failure is received power, whereas for two other events the most influential is the received bit error. After the detected value of the Information Element reaches a certain threshold, MSC will instruct the candidate cell to monitor and serving mobile station. Different process going on for handover (intracell), which after the information element value is known at a certain threshold, MS will move to another traffic channel in the same cell. If handover (intracell) was requested but could not be performed then handover based quality is tried the next time (if criterion is still given). When this handover also fails then BS toggles back and tries again a handover (intracell). In this drive test result there are 15 handover failures that may because no available traffic channel in candidate cell. There is only once handover intracell failure happened which may be caused by full traffic in candidate channel, but no cell reselection failure is found because this event doesn’t need traffic channel but only signaling channel. Keywords: handover, cell reselection, intracell, IE, TEMS
Kompresi Data Berdasarkan Perhitungan Distribusi Probabilitas Kemunculan Karakter Orde Dua Dalam Teks Bahasa Indonesia Christyono, Yuli
TRANSMISI Vol 10, No 1 (2008): TRANSMISI
Publisher : TRANSMISI

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Abstract

In modern world, the need for capacity  data storage and  electronic data communications channel is important. Capacity storage media and channel communication in electronic data that we use at this time is not unlimited and it is quite expensive.Therefore, we need a method to use electronic data storage and communications resource optimally and efficiently. One effort that can do at this time is to perform data compression. Data will be compressed before store or before send, so that storage capacity of the data after compression is smaller than before and economize time to send data after compression. There are many kind of method which used in data compression.This research will study about the theory of probability, calculate distribution probability of character order two of text in indonesian language, coding based on  Huffman theory, and design software  for data compression.Keywords: sandi, kompresi, penyandian, huffman, lossy, lossles
Simulasi Sistem Informasi Geografis (SIG) Pemantauan Posisi Kendaraan Via SMS Gateway Hanifah, Raidah; Isnanto, R. Rizal; Christyono, Yuli
TRANSMISI Vol 12, No 2 (2010): TRANSMISI
Publisher : TRANSMISI

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Abstract

Nowadays a vehicle position monitoring system has started to be built  as its rising demand. A system with capability to trace the position of a vehicle by its owner or third party is well known as vehicle tracking system. This system provide many advantages, therefore in this Final Project a simulation of Geographic Information System (GIS) for Vehicle Position Tracking via SMS Gateway System is made. This system contains two main parts, those are device part and application part. Device part is simulated with a device simulation program. On the other side, application part will show the position information which sent by device par. The information is shown as a graphic with a map as the background. These two parts are developed by Delphi 7.0 programming language and MySQL 5.0 as a database storage. To show the map and mapping functions in this application, an additional program MapObject 2.0 is used. The function of SMS Gateway is connects the device part and application part, and software for this function is Gammu 1.25. This research results a simulation to monitor vehicle position system. The testing results show that this system works properly, and all functions work well as it purposes. The application part shows the position data from device part as pointed tracks in a map. Communication between GIS application part and  device part via Gammu also works properly, with average interval of SMS sending time and receiving time is 17,8 seconds. Keyword :   Geographic Information System (GIS), Position monitoring, SMS Gateway, Gammu.
Aplikasi Sistem Pengendali dan Manajemen Penjadwal Peralatan Listrik dalam Ruangan Firdausi, Aulia Latifah Insan; Sumardi, Sumardi; Christyono, Yuli
TRANSMISI Vol 12, No 2 (2010): TRANSMISI
Publisher : TRANSMISI

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Abstract

Energy crisis is one of the facing globalization problems, and the behavior of energy users like the carelessness in turning the electrical devices on or off are the most significant factor in energy consumption. Therefore, in this final project is made a system for controlling and managing the electrical devices in order to use appropriately needed. This system consists of two main parts, hardware and application. Hardware consists of a master station as the central sending command and two slave stations to execute the sending command. Application will provide information sent to the hardware. Both parts of systems are built with Delphi programming language and MySQL for keeping the database. And the communication between hardware and application use Wireless ZigBee (XBee-PRO) module. This final project results a system for controlling and managing electrical devices based on database to raise the user efficiency. The results show that system can optimize energy consumption and the available technical data information well organized as appropriate as needed. And Wireless ZigBee (XBee-PRO) modules used as communication media between hardware and application have communication range over than 200 meters outdoor and 90 meters in indoor. Keyword :   Controlling and managing application, ZigBee-PRO, database scheduled, Delphi 7.0
Alat Pelacak Lokasi Berbasis GPS Via Komunikasi Seluler Wijaya, Surya Purba; Christyono, Yuli; Sukiswo, Sukiswo
TRANSMISI Vol 12, No 2 (2010): TRANSMISI
Publisher : TRANSMISI

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Abstract

Nowadays, the vehicle’s robbing or the usage of not allowed route is often happen. Therefore, vehicle tracking system is needed to reduce this risk. Vehicle tracking system is a system’s combination  that installed in the vehicle so that can be tracked by the owner or the third part. Modern vehicle tracking system usually use GPS to determine vehicle’s location. This system also usually have communication component such as cellular or satellite to send vehicle’s position to user in another place. In this Final Project, the vehicle tracking tool based on GPS via cellular  will be created. This tool is a part of vehicle tracking system. This tool will respond a command which is sent by tracker via SMS. The device contains of three parts. There are microcontroller as a control part, GPS which provide positioning information, and GSM modem which is used to send or receive message. All of these parts will cooperate to process all of the messages sent by tracker. Then server will get information about position in form of longitude, latitude, date and time. This device will be tested in case of receiving’s delay at tracker side, timer’s precision, location’s precision which is showed by GPS, vehicle tracking. Based on testing, there are varying receiving delay at traker side. Timer has  ran well so that getting data appropriate to the interval which is asked. Position which is showed by GPS is not precision in fact. However, the tracking can be done and similar with the fact in the field.Keyword :   GPS, vehicle tracking system, cellular communication
Aplikasi Pengolahan Citra Digital untuk Mengontrol Saklar Berdasarkan Letak dan Warna Huruf Totalis, Herry; Christyono, Yuli; Zahra, Ajub Ajulian
TRANSMISI Vol 12, No 4 (2010): TRANSMISI
Publisher : TRANSMISI

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Abstract

The use of wireless communication system as a communication medium in control system has been getting popular. Sending information is getting easier with wireless network for example internet. SMS technology has also been used in the house as remote control switch, but there are still many weaknesses including user must know the format of SMS text and have trouble when more and more switches are used. Beside location and condition of the switch in the house is not known directly. Therefore we need a system that can control house’s switch by knowing location and condition directly through pictures.The purpose of this final project research is to design and create a tool that can  control switch remotely using wireless communications with the image display’s position of switch so that we can immediately find out controlled switch . Switch condition is analogue with condition of the  microcontroller pin ATmega8535. In this final project the system is divided into two, namely transmitter and receiver. Transmitter section prepares house plans image data that has been processed and then sent to receiver while receiver interprets image data to determine commands to the microcontroller ATmega8535. Condition of switch can be seen on LED that is connected to microcontroller pin. Based on the test results, it is found that installation image character, changing the color of image character and scanning house plans image in accordance with determined run. Command are sent through serial port properly executed by microcontroller. There’s no error that occur during entire course of the program. In using of ad hoc networks have influencing factors  that is the distance, type of laptops and barrier. Keyword :   transmitter, receiver, house plans image, image character, ad hoc network, serial port,  microcontroller ATmega8535
Perancangan dan Analisis Antena Mikrostrip dengan Frekuensi 850 MHz untuk Aplikasi Praktikum Antena Nugraha, Adhe Setya; Christyono, Yuli; Sukiswo, Sukiswo
TRANSMISI Vol 13, No 1 (2011): TRANSMISI
Publisher : TRANSMISI

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Abstract

Problems antenna of conductor materials is rather complicated construction and size are usually quite large, so for purposes such as a cellular system is considered less efficient. For this purpose requires a simple antenna, a thin, easy to manufacture, and can be connected with other circuits. Then came the idea to design a microstrip antenna that antenna. How to make a microstrip antenna is printed on the plate by the PCB (Printed Circuit Board), then peradiasinya coated with a solution of silver or other conductor material. Who´s lining material that many in the market is epoxy glass fiber (e r = 4.7) with 1.5 mm layer thickness. The purpose of this thesis is to create some models of microstrip antenna that can later be used in practical antenna. The antenna was designed at a frequency of 850MHz with a square, equilateral triangle, and circle. Then the three forms of microstrip antenna design results will be analyzed using software IE3D V12 to obtain the design parameters of antenna and frequency of these antennas. The third form of radiation pattern of microstrip antenna is directional (directional). Results of simulation of microstrip circular antennas : resonant frequency = 0.8535 GHz, VSWR = 1.046, retrun loss = - 32.89 dB, bandwidth = 1.4167%, the total gain = - 0.673953 dB, HPBW = 170,5110, rectangular microstrip antenna : resonance frequency = 0.849503 GHz, VSWR = 1109, return loss = - 25.7143 dB, bandwidth = 1.4547%, the total gain = - 0.205832 dB, HPBW = 170,6550 and for equilateral triangular microstrip antennas : resonant frequency = 0, 8515 GHz, VSWR = 1115, return loss = -25.28 dB, bandwidth = 1.3055%, the total gain = - 2.32265 dB, HPBW = 170,5710. And on the test results obtained for circular microstrip antennas : resonant frequency = 900MHz, VSWR = 1.03, power received = 0.067 mW, HPBW = 620, rectangular microstrip antennas : resonant frequency = 895MHz, VSWR = 1.04, power received = 0.039 mW, HPBW = 880 and antenna for microstrip equilateral triangle : resonance frequency = 895MHz, VSWR = 1.05, power received = 0.033 mW, HPBW = 690. Keywords: microstrip antenna, substrat materials, antenna parameters, the working frequency antenna
Penyembunyian Data Rahasia pada Citra Digital Berbasis Chaos dan Discrete Cosine Transform Prabowo, Anton; Hidayatno, Achmad; Christyono, Yuli
TRANSMISI Vol 13, No 2 (2011): TRANSMISI
Publisher : TRANSMISI

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Abstract

Steganography is one of technique that developed to keep the security of data by hidding or embedding it in other data media so that it’s content or even it’s existence is not notice. Many steganography methode have been developed in the last few years, but it still needed a steganography system with highest capacity and robustness. By combining and modifying few technic, in this Final Project has made a steganography system that used to embedding and extracting secret data in image data form (BMP 8 bit grayscale and 24 bit color), voice data form (WAV PCM 11.025 KHz 8 bit mono), and text data form (TXT) into cover data in image data form (BMP 8 bit grayscale). Data hidding was done at frequency domain by applying DCT (Discrete Cosine Transform) and chaos theory was applied using logistic map equation. Program was made using Borland Delphi 7 programming language. By using subjectif quality, RMS (Root Mean Square) metrics, and similarity ratio measurement parameter, program performance was observed by doing research consist of: research of initialitation parameter change influences; research of embedding and extracting secret digital data in image, voice, and text form into cover digital data in image form; research of program realibility from data manipulation operation including brigthness modification, contrast modification, resizing, cropping, and JPEG compression. Keyword : steganography, discrete cosine transform, chaos theory, logistic map, root mean square.