• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.97-100
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• 2009

The paper describes synchronization schemes for scalable video coding signals over the DVB-S2 network. The MPEG-4 SVC signals include a base layer signal and an enhancement layer signal. They are packetized into MPEG-2 transport streams and transmitted on separate RF channels through the DVB-S2 system. The DVB-S2 receiver is required to synchronize each layer signal together to recover the full pictures. Some new schemes to synchronize two. layered SVC signals in MPEG-4 SVC decoder are proposed and analyzed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.3
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• pp.73-79
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• 1996

In this paper present a new technique (strain-telemetering)for detection of coated tool failure in face milling processes. In the cutter body the strain signals received fro the transmitter is transformed in to frequency modulation(FM) signals in face milling processes. A receiver which is place near by the Vertical milling machine receives the FM signals, then the signals will be sent to a computer which determines whether th tool is failure. And machined surface of workpiece is detected by the SEM. In this paper, A on-line monitoring of the tool failure detection system based on the strain -telemetering apparatus has bee represented.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.11
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• pp.100-105
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• 1996

In this paper presents a new technique (stain-telemetering) for detection of coated tool failure in face milling processes. In the cutter body, the strain signals received from the transmitter are transformed into frequency modulation(FM) signals in face milling processes. The receive which is placed near by the Vertical milling machine receives the FM signals, then the signals are sent to a computer, which shows the tool failure. In this paper, A on-line monitoring of the tool failure detection system based on the strain-telemetering apparatus has been represented.

• Journal of Communications and Networks
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• v.15 no.6
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• pp.569-575
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• 2013

In this paper, we present a photonic approach for generating highly stable coherent sub-terahertz (THz) signals for wireless communications. As proof-of-concept we transmit data at 100 GHz carrier frequency using on-off keying modulation and heterodyne detection. The sub-THz carrier signals are generated by photo-mixing two optical carrier signals at different frequencies, extracted from an optical frequency comb. We introduce a novel system to stabilize the phase of the optical carrier signals. Error-free transmission is successfully achieved up to a bit rate of 8.5 Gbit/s at 100 GHz.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.335-340
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• 2021

A constant envelope multiplexing via constellation tailoring scheme is proposed for flexible power allocation of Global Navigation Satellite System (GNSS) signals. The proposed scheme is compared with the coherent adaptive subcarrier modulation (CASM) adopted in the L1 band signals of the Global Positioning System (GPS) in terms of power difference and power loss. Analysis of the constellation optimization results on the power difference and power loss show that the proposed scheme outperforms the CASM of the GPS signals in the allowable power difference of less than 0.1 dB.

• Smart Media Journal
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• v.8 no.3
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• pp.47-52
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• 2019

In this paper, we designed HW / SW interfaces for processing the signals of capacitive sensors like Electric Potential Sensor (EPS) to detect the surrounding electric field disturbance as feature signals in motion recognition systems. We implemented a smart light control system with those interfaces. In the system, the on/off switch and brightness adjustment are controlled by hand gestures using the designed and fabricated interface circuits. PWM (Pulse Width Modulation) signals of the controller with a driver IC are used to drive the LED and to control the brightness and on/off operation. Using the hand-gesture signals obtained through EPS sensors and the interface HW/SW, we can not only construct a gesture instructing system but also accomplish the faster recognition speed by developing dedicated interface hardware including control circuitry. Finally, using the proposed hand-gesture recognition and signal processing methods, the light control module was also designed and implemented. The experimental result shows that the smart light control system can control the LED module properly by accurate motion detection and gesture classification.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.1
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• pp.59-65
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• 2023

A GNSS receiver must perform signal acquisition to estimate the code phase and Doppler frequency of the incoming satellite signals, which are essential information for baseband signal processing. Modernized GNSS signals have different modulation schemes and long PRN code lengths from legacy signals, which makes it difficult to acquire the signals and increases the computational complexity and time. This paper proposes a novel FFT/Inverse-FFT with baseband resampling to resolve the aforementioned challenges. The suggested algorithm uses a single block only for the FFT and thereby requires less hardware resources than conventional structures such as Double Block Zero Padding (DBZP). Experimental results based on a MATLAB simulation show this algorithm can successfully acquire GPS L1C/A, GPS L2C, Galileo E1OS, and GPS L5.

• Journal of the Optical Society of Korea
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• v.5 no.1
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• pp.25-28
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• 2001

By using an XPM (Cross Phase Modulation) wavelength converter, an all-optical AND gate, which is one of six fundamental logic gates, has been demonstrated. The wavelengths for probe and pump signals are 1553.8 and 1545 nm, respectively. First, characteristics of the XPM wavelength converter have been studied. When both probe and pump signals are driven by high power, the output power of the XPM wavelength is high. Based on this fact and the experiment, the all-optical AND gate has been porved. Probe and pump signals are transformed to pulse signals by using Mach-Zehnder modulator, which is induced by a pulse generator. Square pulse signals that are similar to the format of NRZ signals have been generated. By coupling two pulse signals into the XPM wavelength converter, AND characteristics in substantiated.

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.227-233
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• 2009

We investigated the polarization-mode dispersion (PMD) tolerance for 40Gb/s non-return to zero (NRZ), duobinary NRZ, return to zero (RZ), carrier-suppressed RZ (CS-RZ), and duobinary-carrier-suppressed RZ (DCS-RZ) modulation formats with a forward error correction (FEC) coding. The power penalty has been calculated as a measure of the system performance due to PMD. After comparison of the PMD tolerance of various modulation formats, our results suggest that RZ signals have the best tolerance against the effect of first-order PMD only. The duobinary NRZ modulation format is most resilient to PMD when both first- and second-order PMD are considered. However, the duobinary NRZ modulation format is the most sensitive to the incident angle of the input signal to a fiber axis in the presence of first- and second-order PMD, leading to incident angle-dependent power penalty. The coding gain by FEC can cope with the power penalties induced by first- and second-order PMD up to a DGD value of 16ps.

• Journal of Power Electronics
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• v.8 no.4
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• pp.332-344
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• 2008

High frequency AC (HFAC) power distribution systems delivering power through a high frequency AC link with sinusoidal voltage have the advantages of simple structure and high efficiency. In a multiple module system, where multiple resonant inverters are paralleled to the high frequency AC bus through connection inductors, it is necessary for the output voltage phase angles of the inverters be controlled so that the circulating current among the inverters be minimized. However, the phase angle of the resonant inverters output voltage can not be controlled with conventional phase shift modulation or pulse width modulation. The phase angle is a function of both the phase of the gating signals and the impedance of the resonant tank. In this paper, we proposed a pulse phase modulation (PPM) concept for the resonant inverters, so that the phase angle of the output voltage can be regulated. The PPM can be used to minimize the circulating current between the resonant inverters. The mechanisms of the phase angle control and the PPM were explained. The small signal model of a PPM controlled half-bridge resonant inverter was analyzed. The concept was verified in a half bridge resonant inverter with a series-parallel resonant tank. An HFAC power distribution system with two resonant inverters connected in parallel to a 500kHz, 28V AC bus was presented to demonstrate the applicability of the concept in a high frequency power distribution system.