• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.175-184
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• 2016

In this paper, we propose the method to measure the capacitances using not LCR meter but capacitance to voltage(C/V) conversion. And we design the analog MUX circuits that convert 192 channels to 6 MUX channels in order to implement the diagnosis of multi-channel ultrasonic probe. This paper derives the conversion function that converts the digital voltage of each MUX channel to the capacitance using the least squares method because the circuit characteristics that convert the voltage of each MUX channel to the capacitance are different. The developed prototype illustrates the performance test results that the measure times are measured by within 4sec and the measure error rates of maximum, minimum, and average values are within 5% in terms of the repeated measurements of all 192 channels.

• Composites Research
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• v.14 no.5
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• pp.12-19
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• 2001

In aircraft composite structures, structural defects such as matrix cracks, delaminations and fiber breakages are hard to detect if they are breaking out in operating condition. Therefore, to assure the structural integrity, it is desirable to perform the real-time health monitoring of the structures. In this study, a fiber optic sensor was applied to the composite beams to monitor failure and strain in real-time. To detect the failure signal and strain simultaneously, laser diode and ASE broadband source were applied in a single EFPI sensor using wavelength division multiplexer. Short time courier transform and wavelet transform were used to characterize the failure signal and to determine the moment of failure. And the strain measured by AEFPI was compared with the that of strain gage. From the result of the tensile test, strain measured by the AEFPI agreed with the value of electric strain gage and the failure detection system could detect the moment of failure with high sensitivity to recognize the onset of micro-crack failure signal.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.1
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• pp.129-140
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• 2017

In this paper, a $4{\times}32$-channel neural recording system capable of acquiring neural signals is introduced. Four 32-channel neural recording ICs, complex programmable logic devices (CPLDs), a micro controller unit (MCU) with USB interface, and a PC are used. Each neural recording IC, implemented in $0.18{\mu}m$ CMOS technology, includes 32 channels of analog front-ends (AFEs), a 32-to-1 analog multiplexer, and an analog-to-digital converter (ADC). The mid-band gain of the AFE is adjustable in four steps, and have a tunable bandwidth. The AFE has a mid-band gain of 54.5 dB to 65.7 dB and a bandwidth of 35.3 Hz to 5.8 kHz. The high-pass cutoff frequency of the AFE varies from 18.6 Hz to 154.7 Hz. The input-referred noise (IRN) of the AFE is $10.2{\mu}V_{rms}$. A high-resolution, low-power ADC with a high conversion speed achieves a signal-to-noise and distortion ratio (SNDR) of 50.63 dB and a spurious-free dynamic range (SFDR) of 63.88 dB, at a sampling-rate of 2.5 MS/s. The effectiveness of our neural recording system is validated in in-vivo recording of the primary somatosensory cortex of a rat.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.12
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• pp.35-42
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• 2004

In this paper, we report Mach Zehnder Interleaver of optical fiber type is fabricated by the fabrication system only for interfermeter design, and it is used $CO_2$ laser to adjust precisely the wavelength. The optical fiber is very sensitive in the thermal variation around. Thus, When fabrication the prototype, it is applied a technique to compensate the optical thermal effect because the center wavelength at the output is shifted according to the thermal variation around. it can he done by applying a substrate with high thermal expansion coefficient as well as an adjusting the position between two optical fiber couplers. Consequently, the output wavelength is shifted within 0.05 nm when the surrounding temperature varies until $60^{\circ}C$.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.3
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• pp.125-131
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• 2002

In this paper, a new concatenation scheme of serial concatenated convolutional codes is proposed and the performance analyzed. In the proposed scheme, each of information and parity bits of outer code is entered into inner code through interleaver and deinterleaver. Therefore, the interleaver size is same as the length of input frame. Since the interleaver size of proposed type is reduced to half of the conventional Benedetto type, the interleaver delay time required for iterative decoding is reduced. In addition the multiplexer and demultiplexer are not used in the decoder of the proposed type, the complexity of decoder can be also reduced. As results of simulation, the performance of proposed type shows the better error performance as compared to that of the conventional Benedetto type in case of the same interleaver size. And it can be observed that the difference of BER performance is increased with the increase of Eb/No. In case of the same length of input frame, the proposed type shows almost same performance with Benedetto type despite that the interleaver size is reduced by half.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.11
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• pp.15-21
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• 1999

The scalability of optical cross-connect nodes is analyzed based on the limiting factor of transmission performance. The limiting factors considered are ASE noise accumulation and gain saturation in the optical amplifiers, and crosstalk in both wavelength multiplexers/demultiplexers and optical switches. When the wavelength multiplexer/demultiplexers crosstalk is lower than 25dB, Power Penalty is below 1dB for the cascaded transmission of 10 nodes with 4 input/output ports. When 10Gbps signals are transmitted through nodes with 4 and 16 input/output Ports, performance degradation due to switch crosstalk is dominant compared to that due to ASE noise accumulation if the switch crosstalk is larger than 30dB and 45dB, respectively. For the single stage transmission of 10Gbps signal with 21dB fiber link loss, the maximum loss of optical cross-connect nodes must be under 34dB to achieve the BER of $10^{-12}$.

• Journal of Sensor Science and Technology
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• v.24 no.4
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• pp.252-257
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• 2015

This paper proposes a single slope A/D converter (SSADC) that is possible to process the signal of the ultraviolet, visible and infrared rays with a single chip. And the proposed SSADC is a type of single channel ADC. In the conventional SSADC, it is possible to process the only one signal with a kind of the sensor because the speed of the operating frequency and the slope of ramp signal generated by the ramp generator are fixed. In order to improve the disadvantages, a ramp generator which has variable slope in ramp function is designed and $3{\times}1$ MUX(multiplexer) is adopted so that we can change the speed of the operating frequency and the slope of ramp signal. Therefore, the multiple signal processing of the wanted sensors can be possible. The designed circuit is layout by the $0.35-{\mu}m$ CMOS 2-poly 4-metal technology process and is checked through DRC and LVS tools.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.6
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• pp.51-58
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• 2002

In this paper, a 155/311 Mb/s MUX/DEMUX chip using ECL macrocell away has been developed with a single device. This device for a 2.5 Gb/s SDH based transmission system is to interleave the parallel data of 51 Mb/s into 155 Mb/s(or 311 Mb/s) serial data output, and is to interleave a serial input bit stream of 155 Mb/s(or 311 Mb/s) into the parallel output of 51 Mb/s. The input and output of the device ate TTL compatible at the low-speed end, but 100k ECL compatible at the high-speed end. The device has been fabricated with Motorola ETL3200 macrocell away The fabricated chip shows the typical phase margin of 180 degrees and output data skew less than 220ps at the high-speed end.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.1-8
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• 1999

We analyze the transmission performance of WDM system based on cascaded optical add/drop multiplexers. The considered factors degrading the performance in this paper include the intra-channel corosstalk caused from space switches and demultiplexers/multiplexers, the amplified spontaneous emission noise, and the extinction ratio. To ensure the power penalty within 1dB, the extinction ration more than 13dB, the switch corosstalk less than 39dB, and the demultiplexer/multiplexer crosstalk less than 20dB are required. Under the assumption of switch corosstalk less than 30dB, performance degradation due to the ASE noise is dominant compared to the crosstalk. With the fixed decision threshold in an optical receiver, the maximum number of cascaded nodes reduces to a half compared to the case of the optimum decision threshold.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.471-482
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• 2011

This paper introduces an development of high-definition(HD) 3DTV experimental broadcasting system and its experimental service that has been launched via three broadcasting network including terrestrial, cable and satellite in the late of 2010. This 3DTV experimental broadcasting service employs an innovative 3DTV broadcasting mechanism, called as dual stream method in which left and right images are encoded by using each video encoder and multiplexed using MPEG-2 system technology for guaranteeing backward-compatibility with legacy DTV. This paper specifically describes the developed experimental broadcasting system, concentrating on 3DTV re-multiplexer and 3DTV receiver. Finally, implementation and terrestrial 3DTV experimental broadcasting service results will be introduced from the point of objective and subjective evaluation.