• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.80-89
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• 2010

Transponder is the significant equipment for the telemetry and telecommand operation between the ground station and the satellite. Recently, various transponder technology like Compact Standard Transponder(CST), Small User Transponder(SUT) for data relay satellite, Dual Mode TT&C Transponder(DMT) for large user, and Deep Space Transponder(DST) for deep space mission have been developed according to the communication method and user requirements. Especially, the transponder based on the digital technology comes into the spotlight in the satellite communication field. This paper describes the various analog transponder technology and the state-of-art digital transponder technology grafted onto the existing analog transponder technology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10A
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• pp.807-813
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• 2009

A Satellite transponder is the Communication system to process signal with up-link signal recovery, and transmit to ground station through down-link. The orbit flight in the deep space causes high doppler shift in the received signals from the ground station so that the Carrier recovery and fast synchronization system are essential for the transponder system. The conventional analog transponder is employing the system's carrier recovery along with the PLL (Phase Locked Loop) designed for satellite's operation. This paper presents a digital carrier recovery scheme which can provide more reliable and software reconfigurable implementation technique for satellite transponder system without verifying scheme along with transponder designed for short distance or deep space satellite.

• Transactions on Electrical and Electronic Materials
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• v.11 no.1
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• pp.20-23
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• 2010

The analog front end (AFE) of a radio frequency identification transponder using the ISO 14443 type A standard with a 100% amplitude shift keying (ASK) modulation is proposed in this paper and verified by circuit simulations and measurements. This AFE circuit, using a 13.56 MHz carrier frequency, consists of a rectifier, a modulator, a demodulator, a regulator, a power on reset, and a dynamically enabled digital phase locked loop (DPLL). The DPLL, with a charge pump enable circuit, was used to recover the clock of a 100% modulated ASK signal during the pause period. A high voltage lateral double diffused metal-oxide semiconductor transistor was used to protect the rectifier and the clock recovery circuit from high voltages. The proposed AFE was fabricated using the $0.18\;{\mu}m$ standard CMOS process, with an AFE core size of $350\;{\mu}m\;{\times}\;230\;{\mu}m$. The measurement results show that the DPLL, using a demodulator output signal, generates a constant 1.695 MHz clock during the pause period of the 100% ASK signal.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.1
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• pp.56-62
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• 2011

A Satellite transponder is mounted on the Satellite and performs radio communications with the ground station. A Digital transponder compared to The analog transponder is made easy and accurate performance prediction. Also Modulation Scheme, Data Rate, Loop Bandwidth, Modulation Index and etc. can be changed on orbit, by implementing FPGA can reduce the weight and volume. The core technology of digital transponder is Carrier Recovery loop. Dynamic Range, Frequency Tracking Range, Frequency Tracking Rate and Coherent performance are determined by the performance of the Carrier Recovery loop. In this paper, we proposed the structure of Carrier Recovery loop for the Satellite digital transponder, then tested and verified the structure.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.47-56
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• 2008

An RFID system comprises a reader and a tag, and this paper focuses on a tag design. A UHF tag is activated by energy supply using electromagnetic waves and energy reflection through impedance mismatching. The tag uses a $0.25{\mu}m$ CMOS process and comprises a digital part executing tag protocols, a 512-bit memory, and an analog part having a rectifier, a modulation/demodulation unit, a clock generator, etc. The total dimension of the tag, including a saw line, is $750{\mu}m*750{\mu}m$ and the power consumption of the tag consumption power is about $17.8{\mu}W$ at a supply voltage of 2V.