• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.69-78
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• 1999

In this paper, direct conversion receiver was designed to even harmonic anti-paralled diode pair ring mixer. Using a second harmonic component of LO instead of LO signal and RF signal are mixed by SHP(Sub Harmonic Pumped) mixer with anti-parallel diode pair. Canceling the harmonics of LO signal in ring mixer, SHP mixer using anti-parallel diode pair could mostly reduce the radiation of LO signal through a input port the most, good isolation characteristic, and low spurious characteristic by LO signal was shown over broad band. The produced SHP mixer showed LO/IF, RF/IF and LO/RF isolation was 24.6dB,36.2dB and 22.5dB respectively. And conversion loss was measured 15.6dB, IF output -35.6dBm with -20dBm RF input and 5.5dBm LO signal. 1dB compression point of If signal, in respect to RF signal, was found at the 0dbm RF signal.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.501-509
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• 2011

Software defined radio(SDR) has a goal that places the analog-to-digital converter(ADC) as near the antenna as possible. But current technique actually can't do analog-to-digital converting about RF band signals. So one method is studying that samples RF band signals to IF band. One of the ways Sub-Sampling technique can convert signals from RF band to IF band without oscillator. If Sub-Sampling technique is used, over 2 bands can convert signals from RF band to IF band. But due to the filter performance in RF band, it is possible to generate interference between signals that is converted in low frequency band. The effect degrades performance. In this paper, we propose one method that uses time division multiplexing(TDM) method as a solution to avoid interference between signals. By doing TDM and Sub-Sampling at the same time that method can get signals without large changes of structures.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.3
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• pp.305-310
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• 2015

In this paper, a wireless spectrum sensing receiver system is proposed. While a conventional Cognitive Radio(CR) system utilizes frequency down-conversion and demodulation to recognize wireless spectral signal, the proposed one is able to recover and sense valid signal at an RF front-end. It has been designed with a super-regeneration type circuit with a channel selectivity and variability for FDM applications with which a conventional single-channel super-regeneration circuit could not provide. From experimental evaluation, the implemented system has been optimized for channel allocation with quenching signal, and verified for 5 MHz-channel spacing.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.6 s.336
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• pp.1-8
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• 2005

This paper presents a new low-cost fault-based Built-In Self-Test (BIST) scheme and technique for 1.8GHz RF receiver front end. The technique utilizes input impedance matching measurement. The BIST block and RF receiver front end are designed using 0.25m CMOS technology on a single chip. The technique is simple and inexpensive. The overhead of the BIST circuit is approximately $10\%$ of the total area of the RF front end.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.45-50
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• 2002

A conceptual design on the link budget of TC&R RF subsystem which transfers command and telemetry data as RF signal between the ground system and the 2005SAT spacecraft is presented in this paper. In order to perform the analysis of the link budget, we divided the analysis process into two processes, i.e., uplink and downlink process. For the uplink the power flux density at the spacecraft and the margin of the command receiver are calculated. In the case of the downlink the downlink EIRP and the margin of C/ No and Eb / No at the ground station are calculated. Through the uplink performance analysis, the power at the command receiver has well efficient margin, and the margin of C/ No and Eb / No is also fully proper for the downlink case.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.97-97
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• 2000

In this paper, a signal processing algorithm for software GPS receiver is proposed. The signal processor takes snapshot of the sampled If signal from the RF section of the GPS receiver. All the processing for code and carrier tracking and correlation are implemented using the digital signal processing techniques. In order to achieve fast code acquisition, correlation of the incoming GPS signal is performed using the FFT method, After code acquisition, to reduce the Doppler shift effect and increase the accuracy, the interpolation or the tracking are performed. The performance of the proposed processing algorithm is first evaluated using matlab/simulink. A signal acquisition board for sampling and logging GPS IF signal form the Mitel GPS RF chip set is constructed. In order to analyze the performance of the designed algorithm the experiments are performed and the results are analyzed.

• Journal of Advanced Navigation Technology
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• v.1 no.1
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• pp.23-34
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• 1997

A multi-channel digital GPS receiver has been developed including a RF-to-IF engine (engine 1), a digital signal processing engine (engine 2) with a microprocessor interfacing, and a navigation software. A high speed SiGe heterojunction bipolar transistor (HBT) as a active device has been mounted on chip-on-board (COB) type hybrid ICs such as LNA, mixer, and VCO in RF front-end of the engine 1 board. A 6-channel digital correlator together with a real-time clock and a microprocessor interface has been realized using an Altera Flex 10K FPGA as well as ASIC technology. Navigation software controlling the correlator for GPS signal tracking, retrieval and storing a message retrieval, and position calculation has been implemented. The GPS receiver was tested using a single channel STR2770 simulator. Successful navigation message retrieval and position determination was confirmed.

• Journal of Korea Multimedia Society
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• v.9 no.12
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• pp.1669-1680
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• 2006

This paper explains that the RF systems for hi-directional wireless capsule endoscopes were designed and implemented. The designed RF systems for a capsule endoscope can transmit the images of intestines from the inside to the outside of a body and the behavior of the capsules can be controlled by an external controller simultaneously. The hi-directional wireless capsule endoscope consists of a CMOS image sensor, FPGA, LED, battery, DC to DC Converter, transmitter, receiver, and antennas. The transmitter and receiver which were used in the hi-directional capsule endoscope, were designed and fabricated with $10mm(diameter){\times}3.2mm(thickness)$ dimensions taking into the MPE, power consumption, system size, signal to noise ratio and modulation method. The RF systems designed and implemented for the hi-directional wireless capsule endoscopes system were verified by in-vivo experiments. As a result, the RF systems for the hi-directional wireless capsule endoscopes satisfied the design specifications.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.4
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• pp.506-517
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• 2015

This paper presents a 1.248 Gb/s - 2.918 Gb/s low-power receiver MIPI-DigRF M-PHY with a fully digital frequency detection loop. MIPI-DigRF M-PHY should be operated in a very short training time which is $0.01{\mu}s$ the for HS-G2B mode. Because of this short SYNC pattern, clock and data recovery (CDR) should have extremely fast locking time. Thus, the quarter rate CDR with a fully digital frequency detection loop is proposed to implement a fast phase tracking loop. Also, a low power CDR architecture, deserializer and voltage controlled oscillator (VCO) are proposed to meet the low power requirement of MIPI-DigRF M-PHY. This chip is fabricated using a $0.11{\mu}m$ CMOS process, and the die area is $600{\mu}m{\times}250{\mu}m$. The power consumption of the receiver is 16 mW from the supply voltage of 1.1 V. The measured lock time of the CDR is less than 20 ns. The measured rms and peak jitter are $35.24ps_{p-p}$ and $4.25ps_{rms}$ respectively for HS-G2 mode.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.225-228
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• 2004

This paper has been studied about UWB(Ulra wide-band)'s LNA(Low Noise Amplifier) and Mixer. The UWB is a new technology that is being pursed for both commercial and military purposes. Direct conversion architectures that convert RF signals have potential to achieve such terminals, because they eliminate the need for non-programmable image-rejection filters and IF channel filters. And this architecture promises better performance in power, size, and cost than existing heterodyne - based receivers. This Receiver architectures combines low-noise amplifier, mixer. And then this paper has designed suitable UWB's LNA and Mixer.