• Journal of the Korea Institute of Military Science and Technology
• /
• v.18 no.3
• /
• pp.275-282
• /
• 2015

Recently, telemetry systems are used to test and evaluate of ammunition. When a transmitting signal from a small transmitter mounted inside the ammunition is sent out, the receiving equipments get real-time RF data. This paper relates to the development of a small high-G endurable transmitter and a portable receiving equipment. The system was tested and confirmed 00 km communication range.

• Proceedings of the IEEK Conference
• /
• 2004.06b
• /
• pp.411-414
• /
• 2004

This paper introduces a modulation method for digital wireless communication based on general DS-QPSK. The design and fabrication is for home networking application to a typical RF transmitter with DS-QPSK modulator. This modulator implemented using VHDL hardware programming language, the fabrication of IC chip $5{\times}5 mm^2$ was carried by 27th IDEC MPW(Multi Project Wafer) process in 0.35${\mu}m$ rule at Samsung Inc. This paper presented the important of this technology for the future application in wireless sensor. This module can be efficient usage for home network to transmit the RF wireless sensor system.

• Journal of Biomedical Engineering Research
• /
• v.21 no.5
• /
• pp.513-517
• /
• 2000

In this study, we fabricated the advanced telemetry system that transmitting media use radio frequency(RF) for the middle range measurement of the physiological signals and receiving media use optical for electromagnetic interference problem. The telemetry system within a size of 65$\times$125$\times$45mm consists of three parts: a RF transmitter, a optical receiver and a physiological signal processing CMOS one chip. Advantages of proposed telemetry system is wireless middle range(50m) FM transmission, reduce electromagnetic interference to a minimum which enables a comfortable bed-side telemetry system.

• Aerospace Engineering and Technology
• /
• v.7 no.1
• /
• pp.121-128
• /
• 2008

In the department of mobile communication technology and satellite communication technology, wireless communication technology division is very important by transmitting and receiving the signals in wireless link environment. Most of all, the components which comprises the transmitter and receiver can decide the RF(Radio Frequency) system performances. Therefore to assure the reliability in the satellite communication field, it is essential to acquire the competitiveness by developing the highly integrated and compact components by means of MMIC(Monolithic Microwave Integrated Circuit) technology. MMIC is the designing and fabricating technology for the RF components. This paper introduces the MMIC technology and describes the technological trend and prospect in the satellite application.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.3 no.2
• /
• pp.329-337
• /
• 1999

In this dissertation, the characteristics of W-CDMA(Wideband CDMA) are studied and required specifications of IMT-2000 transceiver using W-CDMA method are proposed. Also, in order to design the RF circuits satisfied the proposed specifications, theoretical models are expanded and real circuits are made. Then the RF circuits of the mobile stations are implemented in the three parts, transmitter, receiver and frequency synthesizer and are evaluated. The frequency synthesizer is designed using techniques of swallow counter and passive 3rd loop filter. For improving characteristics of the loop, a LPF was added to the 2nd loop filter. So although the locking times are loosed, the spurious are reduced. The output power of transmitter is over 50mW, the spurious output is -40dB/30kHz at 5MHz offset and power control range is -20dB at 2.5V. The proposed specifications are considered in highly practical environment and the theoretical designs and the experiments are expressed as simply as possible in order to facilitate understanding. It stands to reason that the results of this study can be used to design the wider CDMA(25MHz Bandwidth) mobile communication systems.

• The Journal of the Korea Contents Association
• /
• v.6 no.1
• /
• pp.8-13
• /
• 2006

In this thesis, an automatic door lock system using a dual tone multiple frequency(DTMF) signal generated as pushing the key button of mobile phone is proposed and implemented. This system consists of a transmitter module and a receiver module for processing the DTMF signal of mobile phone. The DTMF signal of mobile phone connected with ear-phone jack enter into the input terminal of DTMF receiver and those are encoded by a code-converter with 4-bits binary format in the DTMF receiver. The encoded output signals are transmitted to the amplitude shift keying(ASK) modulator of transmitter module and the modulated ASK signals which are converted into radio frequency(RF) signals propagate in a free space. The RF signals passed through a free space are demodulated by the ASK demodulator of receiver module and the demodulated ASK signals are sent to a micro-controller unit(MCU). The output signals processed by the MCU are compared with the secreted identification number which is prerecorded in a microprocessor and are transferred to a power relay. If the result is the same, the automatic door lock system opens a door. In the opposite case, it maintains closing the door. The implemented automatic door lock system operates well in mobile environments.

• IEIE Transactions on Smart Processing and Computing
• /
• v.3 no.4
• /
• pp.221-225
• /
• 2014

Low power RF devices, such as RFID and Zigbee, are important for ubiquitous sensing. These devices, however, are powered by portable energy sources, such as batteries, which limits their use. To mitigate this problem, this study developed RF energy harvesting with W-CDMA for a low power RF device. Diodes are required with a low turn on voltage because the diode threshold is larger than the received peak voltage of the rectifying antenna (rectenna). Therefore, a Schottky diode HSMS-286 was used. A prototype of RF energy harvesting device showed the maximum gain of 5.8dBi for the W-CDMA signal. The 16 patch antennas were manufactured with a 10 dielectric constant PTFT board. In low power RF devices, the transmitter requires a step-up voltage of 2.5~5V with up to 35 mA. To meet this requirement, the Texas Instruments TPS61220 was used as a low input voltage step-up converter. From the evaluated result, the achievable incident power of the rectenna at 926mV to operate Zigbee can be obtained within a distance of 12m.

• Journal of IKEEE
• /
• v.20 no.1
• /
• pp.54-60
• /
• 2016

In this paper, out-of-band emission regulations and measurement methods of terrestrial DTV broadcasting services are analyzed, and a novel method to evaluate the out-of-band emission characteristics of DTV transmitter is proposed. Experimental results show that proposed method can be easily used to measure the characteristics of DTV transmitter with inexpensive measuring equipments. With a few modifications, proposed method can be widely adopted to measure the RF performances of the general radio equipments efficiently.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.8 no.1
• /
• pp.61-72
• /
• 1997

The implementation of base station transceiver for Wideband CDMA(Code Division Multiple Access) PCS(Personal Communication Service) system using spread spectrum CDMA technology is presented in this paper. The receiver that requires wide dynamic range and high sensitivity and the transmitter that has good spurious emission supression were designed and implemented with 5 MHz RF channel bandwidth. This paper shows the some factors that should be considered and simulated using the RF simulation S/W with commercial and customized components. The implemented transceiver based on the simulation gave good results that satisfied the functional specifications of the transceiver.

• ETRI Journal
• /
• v.41 no.4
• /
• pp.536-548
• /
• 2019

In this study, an electronically steerable parasitic array radiator (ESPAR) antenna via analog radio frequency (RF) switches for a single RF chain MIMO system is presented. The proposed antenna elements are spaced at ${\lambda}/64$, and the antenna size is miniaturized via a dielectric radome. The optimum reactance load value is calculated via the beamforming load search algorithm. A switch simplifies the design and implementation of the reactance loads and does not require additional complex antenna matching circuits. The measured impedance bandwidth of the proposed ESPAR antenna is 1,500 MHz (1.75 GHz-3.25 GHz). The proposed antenna exhibits a beam pattern that is reconfigurable at 2.48 GHz due to changes in the reactance value, and the measured peak antenna gain is 4.8 dBi. The reception performance is measured by using a $4{\times}4$ BPSK signal. The measured average SNR is 17 dB when using the proposed ESPAR antenna as a transmitter, and the average SNR is 16.7 dB when using a four-conventional monopole antenna.