Osman Ceylan

Implementation of a software defined FM mixed demodulator on FPGA

Software defined radio (SDR) applications are usually preferred in low power flexible communication systems. In this paper, a software defined Frequency Modulation (FM) demodulator is presented. Mixed demodulation technique is used to build a digital FM demodulator which has 16 MHz sampling rate. Proposed system was implemented successfully on a Field Programmable Gate Array (FPGA). The system uses 1247 logic elements. FPGAs power consumption is 113.56 mW. The system was tested and verified with a test bed including Analog Digital Converter (ADC) and Digital Analog Converter (DAC).

Low cost S Band communication system design for nano satellites

Nano satellite structures have limited communication ability due to limited power and size. Most of satellite includes sensors, for instance camera, also image transfer requires more data transfer speed. In this project, 2.4 GHz (S Band) communication system is designed for LEO satellites (700–900 km). System includes system-on-chip transmitter device, preamplifier, band pass filter, power amplifier and microstrip antenna array. Microstrip antenna array and RF circuit is designed on FR4. Microstrip array size is 92×84mm2 and RF circuit size is 38×53mm2. Output power of the system is 35dBm for 2.4kbaud data rate, but it can be increased to power capability of the satellite for more data rate.

Received Signal Strength Technique Performance in Sensor Network Localization Application

In this paper, we initially present RSSI vs Distance test results performed indoor and outdoor with Texas Instruments CC2431 Development Kit. In addition, Location Engine of Development Kit performance is presented with 3 and 4 reference nodes. An alternative algorithm based on Cayley-Menger Determinant, proposed by M.Cao, B.D.O. Anderson and A.S. Morse has been implemented in Matlab and it is compared with Location Engine. It is concluded that accuracy of alternative one slightly better than Location Engine with 3 reference nodes. Increasing reference node count makes Location Engine more accurate.

High speed downlink system for small satellite and high-efficiency x-band GaN SSPA

A high-speed downlink communication system is required to meet various applications for nano/small satellites. The purpose of this research is to develop a high-data-rate X band downlink system with low power consumption. A high efficient RF circuits using GaN-HEMT SSPA and low power consumption digital circuits were important. We developed over 300Mbps with occupied BW150MHz, RF power 2W, power consumption 20W, mass 1.4kg.

The X(-Band) Files: An X-Band Microstrip Voltage-Controlled Oscillator with Wideband Tuning Range

Signal sources are essential devices for radar and communication systems. The demand for oscillators has existed for very long time. In 1888, Heinrich Hertz introduced the first known oscillator to prove Maxwells equations experimentally [1]. He used a dipole as the frequency determining structure and a spark-gap generator as the signal source. His invention signaled the birth of wireless communications because Hertz confirmed the existence of electromagnetic radiation which was postulated by Michael Faraday and James Clerk Maxwell.

Effects of substrate thickness and dielectric to microstrip dipol antenna parameters for 2.4 GHz wireless communication devices

İt is aimed to design 2.4 GHz microstrip-dipole antennas for wireless communication systems by using different substrates with different physical properties in this paper. Designs were made according to general microstrip dipole structure. Ansoft HFSS programme was used for simulations of antennas and simulations were used to indicate effects of substrate thickness, tangent loss and dielectric to antenna.

Yazılım Tanımlı Radyo Tabanlı FM Demodülatör Tasarımı

Bu calismada, yazilim tanimli radyo tabanli karma yapili FM demodulator Sahada Programlanabilir Kapi Dizileri (FPGA) uzerinde gerceklenmis ve test edilmistir. Tasarimda kullanilan tum alt moduller donanim tanimlama dili olan VHDL ile tasarlanmistir Yazilimsal uygulamalarda onemli olan esneklik, kaynaklarin verimli kullanimli ve dusuk guc tuketimi konularinda iyilesme hedeflenmistir. Tasarlanan sistem Cyclone IV model FPGA uzerinde 1247 tane mantiksal birim kullanilarak tasarlanmistir. FPGA’nin guc tuketimi 113.56 mW, veriler arasi maksimum gecikme suresi ise 9.773 ns’dir. Onerilen ve tasarlanan yapi ile daha once yapilmis ve yayinlanmis olan karma demodulator yapilarina gore daha az kaynak kullanilmis ve toplam gecikme suresi dusurulmustur.

Design of a circularly polarized microstrip antenna array at 2.45 GHz

In this work, a circularly polarized antenna array operating at 2.45 GHz has been designed. This kinds of antennas should match the gain requirement of the system in order to communicate with experimental small satellites as they are used as ground station antennas. The easiest way to prevent polarization loss between receiver and transmitter because of unstable movement of the satellite which can go up to a few kilometers is to use circularly polarized antennas. In this work a 4 element circularly polarized antenna array has been designed using sequential rotation technique. As a result it has been seen that the return loss bandwidth is about 9 percent and axial ratio bandwidth is capable of covering ISM 2.4 band. It has been seen that maximum gain of the antenna is above 8dBic.

HAVELSAT: A software defined radio experimentation CubeSat

Despite the small amount of available volume, CubeSat missions have proven to be quite useful, especially for scientific data gathering, educational purposes and small scale industrial equipment testing. The aim of this article is to discuss the design principles and project goals of a CubeSat that is part of the QB50 project. HAVELSAT is a double-unit CubeSat with one functional and one scientific unit. The scientific payload of HAVELSAT is a Software Defined Radio for communication. The satellite also performs a small scale onboard image processing.

Radio trasmitter design including FPGA for micro/nano satellite

In recent years, small satellites have begun to draw attention due to reconstruction in low cost of manufacture and faster building time. In this project, radio transmitter system is built for nano and micro satellites. Transmitter broadcasts 1W power in 435 MHz free amateur satellite communication band, and also has software defined radio structure in all modules except upconvertion part. Design was capable of DE0-Nano evaluation board connection; it is regard of PC104 connector structure standard. FSK modulation and AX.25 data link layer protocol are designed using digital circuit in FPGA and implemented with VHDL.