• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.6
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• pp.28-36
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• 2008

This paper describes a low-power CMOS analog front-end block for UHF band RFID tag chips. It satisfies ISO/IEC 18000-6C and includes a memory block for test. For reducing power consumption, it operates with an internally generated power supply of 1V. An ASK demodulator using a current-mode schmitt trigger is proposed and designed. The proposed demodulator can more exactly demodulate than conventional demodulator with low current consumption. It is designed using a $0.18{\mu}m$ CMOS technology. Measurement results show that it can operate properly with an input as low as $0.25V_{peak}$ and consumes $2.63{\mu}A$. The chip size is $0.12mm^2$.

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

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.1
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• pp.120-128
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• 2017

This paper describes a neural stimulation system that employs an inductive coupling link to transfer power and data wirelessly. For the reliable data and power delivery, a self-referenced amplitude-shift keying (ASK) demodulator and a wide-range voltage regulator are suggested and implemented in the proposed stimulator system. The prototype fabricated in 0.35 um BCD process successfully transferred 1.2 Kbps data bi-directionally while supplying 4.5 mW power to internal MCU and stimulation block.

• 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 Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.130-136
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• 2008

This paper describes a low-power high-performance analog front-end block for $UHF(860{\sim}960MHz)$ band RFID tag chips. It satisfies ISO/IEC 18000-6 type C(EPCgolbal class1. generation2.) and includes a memory block for test. For reducing power consumption, it operates with a internally generated power supply of 1V. An ASK demodulator using a current-mode schmitt trigger is proposed and designed. The proposed demodulator has an error rate as low as 0.014%. It is designed using a 0.18um CMOS technology. The simulation results show that the designed circuit can operate properly with an input as low as $0.2V_{peak}$ and consumes $2.63{\mu}A$. The chip size is $0.12mm^2$

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.166-168
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• 2006

An analog front-end circuit for 13.56MHz ISO/IECl4443 type B compatible RFID tags was designed. The designed circuit includes a rectifier and regulator to generate a stable DC voltage from the RF signal, an over-voltage limiter to protect the circuit from high voltages, an ASK demodulator to extract the data transferred from reader to tag, and a load modulator to transfer data from tag to reader. The functionality of the designed circuit has been verified through simulations using 0.25um CMOS process parameters.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.79-85
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• 2004

In this paper, the RF-ID system for ubiquitous tagging applications has been designed, fabricated and analysed. The RF-ID System consists of passive RF-ID Tag and Reader. The passive RF-ID tag consists of rectifier using zero-bias schottky diode which converts RF power into DC power, ID chip, ASK modulator using bipolar transistor and slot loop antenna. We suggest an ASK undulation method using a bipolar transistor to compensate the disadvantage of the conventional PIN diode, which needs large current Also, the slot loop antenna with wider bandwidth than that of the conventional patch antenna is suggested The RF-ID reader consist of patch array antenna, Tx/Rx part and ASK demodulator. We have designed the RF-ID System using EM and circuit simulation tools. According to the measured results, The power level of modulation signal at 1 m from passive RF-ID Tag is -46.76 dBm and frequency of it is 57.2 KHz. The transmitting power of RF-ID reader was 500 mW

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1A
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• pp.58-64
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• 2006

A 900-MHz band transceiver has been developed for RFID reader applications. In the transmitter, a GaAs SPST switch is used for high speed switching and low power consumption. In the receiver, a double balanced mixer is used to compress even-harmonic products. The ASK demodulator which consists of an active filter and comparator is used to reject the unwanted in band interferers. The transceiver produces a maximum transmitting power of 30 dBm and exhibits an 5 m communication range with a 6-dBi gain antenna.

• Journal of IKEEE
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• v.22 no.2
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• pp.432-439
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• 2018

In this paper, an omnidirectional visible light detector was developed by making the detecting surface of a flexible solar cell in a cylindrical form, which has a uniform receiving pattern in the horizontal plane. This solar cell detector receives simultaneously multiple signal lights incident from different directions and provides electrical power to the ASK demodulator in the receiver. In experiments, time division transmission method was used to receive three signal lights incident from different directions to the solar cell detector. Each signal light was ASK modulated using a carrier of 40 kHz, and the synchronizing pulses required for time division transmission were generated by detecting the 120 Hz AC signal included in the indoor illumination lamp with Cds cells. This receiving structure is useful in constructing an $N{\times}1$ optical link in visible light communication.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.10
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• pp.45-52
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• 2008

We investigated the design of an RF-powered, wireless temperature sensor tag chip using $0.18-{\mu}m$ CMOS technology. The transponder generates its own power supply from small incident RF signal using Schottky diodes in voltage multiplier. Ambient temperature is measured using a new low-power temperature-to-voltage converter, and an 8-bit single-slope ADC converts the measured voltage to digital data. ASK demodulator and digital control are combined to identify unique transponder (ID) sent by base station for multi-transponder applications. The measurement of the temperature sensor tag chip showed a resolution of $0.64^{\circ}C/LSB$ in the range from $20^{\circ}C$ to $100^{\circ}C$, which is suitable for environmental temperature monitoring. The chip size is $1.1{\times}0.34mm^2$, and operates at clock frequency of 100 kHz while consuming $64{\mu}W$ power. The temperature sensor required a -11 dBm RF input power, supported a conversion rate of 12.5 k-samples/sec, and a maximum error of $0.5^{\circ}C$.