• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.13 no.2
• /
• pp.123-128
• /
• 2020

A low phase noise phase locked loop (PLL) with negative feedback loop including frequency variation sensing circuit (FVSC) has been proposed. The FVSC senses the frequency variation of voltage controlled oscillator output signal and controls the volume of electric charge in loop filter capacitance. As the output frequency of the phase locked loop increases, the FVSC reduces the loop filter capacitor charge. This causes the loop filter output voltage to decrease, resulting in a phase locked loop output frequency decrease. The added negative feedback loop improves the phase noise characteristics of the proposed phase locked loop. The size of capacitance used in FVSC is much smaller than that of loop filter capacitance resulting in no effect in the size of the proposed PLL. The proposed low phase noise PLL with FVSC is designed with a supply voltage of 1.8V in a 0.18㎛ CMOS process. Simulation results show the jitter of 273fs and the locking time of 1.5㎲.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.25 no.4
• /
• pp.238-246
• /
• 2015

A stepping motor is widely used to operate the elevation and azimuth stage of the X-band antenna with 2-axis gimbal system for effective image data transmission from a satellite to a ground station. However, such stepping motor also generates an undesirable micro-vibration which is one of the main disturbance sources affecting image quality of the high-resolution observation satellite. In order to improve the image quality, the micro-vibration isolation of the X-band antenna system is essential. In this study, the low rotational stiffness isolator has been proposed to reduce the micro-vibration disturbance induced by elevation direction operation of the X-band antenna. In addition, its structural safety was confirmed by the structure analysis based on the derived torque budget. The effectiveness of the design was also verified through the micro-vibration measurement test.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.2
• /
• pp.228-238
• /
• 2003

We believe that existing wire solutions such as HomePNA2.0 using phone lines and HomePlug using power line and wireless solution such as HomeRF are the most promising solutions, because of its cost-effectiveness. However, MAC protocols of these solutions provide only Class of Service(CoS) using priority mechanism like HomePNA and HomePlug or consider only voice among real-time traffics like HomeRF. For these reasons, we perceive the needs of the new MAC protocol which is no new wire solution and provides guaranteed Quality of Service (QoS) for not only voice but also video and audio. In light of this, we present the design and software implementation of a new MAC protocol for Home Networks. Our evaluation results of software implementation verify that proposed MAC protocol can provide low delay, low loss, and low jitter to real-time traffic by reserving bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.12C
• /
• pp.255-260
• /
• 2001

This paper describes the design of the Register Controlled DLL(Delay-Locked Loop) that achieves fast locking and low Power consumption using a new locking algorithm. A fashion for a fast locking speed is that controls the two controller in sequence. The up/down signal due to clock skew between a internal and a external clock in phase detector, first adjusts a large phase difference in coarse controller and then adjusts a small phase difference in fine controller. A way for a low power consumption is that only operates one controller at once. Moreover the proposed DLL shows better jitter performance Because using the lock indicator circuit. The proposed DLL circuit is operated from 50MHz to 200MHz by SPICE simulation. The estimated power dissipation is 15mA at 200MHz in 3.3V operation. The locking time is within 7 cycle at all of operating frequency.

• The KIPS Transactions:PartB
• /
• v.18B no.6
• /
• pp.397-404
• /
• 2011

In this paper, we were carried out experiments to apply parameter of voice analysis to measure changing characteristic articulator according to inhale the helium gas. The helium gas was used to overcome air embolism nitrogen gas to deal a fatal blow in body nitrogen gas by diver. However, the helium gas has been much trouble interpretation about abnormal voice of diver to cause squeaky voice of low articulation. Therefor, we was carried out experiments about pitch and spectrogram measurement, analysis based on to influence in acoustic organs before and after of inhaled helium gas.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.1
• /
• pp.90-96
• /
• 2014

This paper presents a practical linearization technique for a wide-band bang-bang digital phase locked-loop(BBDPLL) by selecting optimal loop gains. In this paper, limitation of the theoretical design method for BBDPLL is explained, and introduced how to implement practical BBDPLLs with CMOS process. In the proposed BBDPLL, the limited cycle noise is removed by reducing the proportional gain while increasing the integer array and dither gain. Comparing to the conventional BBDPLL, the proposed one shows a small area, low power, linear characteristic. Moreover, the proposed design technique can control a loop bandwidth of the BBDPLL. Performance of the proposed BBDPLL is verified using CppSim simulator.

• Phonetics and Speech Sciences
• /
• v.3 no.2
• /
• pp.99-105
• /
• 2011

The treatment for patients with mutational dysphonia typically is useful with vegetative phonation, but has not yet been studied. This study attempts to identify the effect of $SKTCLP^{(R)}$ using throat clearing and laughing in patients with mutational dysphonia. The study, which was designed by the author, included 26 patients aged from 14 to 32 years (mean: 18.7 years) who had been diagnosed with mutational dysphonia between January 2007 and June 2010. Voice therapy for these patients included $SKTCLP^{(R)}$, ranging from two to seven sessions (mean: 3.8 sessions). Results were evaluated by videostroboscopy, perceptual evaluation of GRBAS scale, aerodynamic test, and acoustic analysis before and after therapy. Most patients could phonate with low pitch from the beginning and sustain with normal pitch sound in the last session. We had found that glottic gap reduced after therapy and anterior-posterior compression of superior laryngeal part at the first time, and these patients had complete closure of the glottis after treatment. The results of acoustic and aerodynamic measures after treatment indicated significant decreases in Fo, Jitter, Shimmer, SFF, and SPI, and increases in MPT, Psub, and vocal efficiency (p<.05). $SKTCLP^{(R)}$ may be a useful treatment method in managing mutational dysphonia. We can suggest this technique may be useful in improving the voice quality of other functional dysphonia having glottal chink or functional aphonia.

• Korean Journal of Optics and Photonics
• /
• v.10 no.5
• /
• pp.364-368
• /
• 1999

We investigate the evaluation items of LSU (Laser Scanning Unit), such as beam size, f$\theta$ characteristics, linearity, skew and bow, optical power ratio between image height of 0mm and $\pm$108 mm, pitch error, Jitter and shift of printing position. Through the measurement of LSU using BSH (Beam Scan Head) installed on LMC (Linear Motion Controller) which moves linearly within the whole scanning range (-108 mm~+108 mm), we can ascertain plastic f$\theta$ lenses, which are manufactured by TVLP (Two-step Variable Low Pressure) molding method, to satisfy 600DPI(Dots Per Inch) performance.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.11 no.3
• /
• pp.48-54
• /
• 2012

The quality of real-time voice communication over Internet Protocol networks based on telematics is affected by network impairments such as delays, jitters, and packet loss. To resolve this issue, this paper proposes a receiver-based enhancing method of VoIP speech quality. The proposed method enables users to deliver high-quality voice using playout control and signal reconstruction, which consists of concealment of lost packets, adaptive playout-buffer scheduling using active jitter estimation, and smooth interpolation between two signals in a transition region. The proposed algorithm achieves higher Perceptual Evaluation of Speech Quality (PESQ) values and low buffering delay than the reference algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.7
• /
• pp.2936-2951
• /
• 2016

An emerging satellite technology, Operationally Responsive Space (ORS) is expected to provide a fast and flexible solution for emergency response, such as target tracking, dense earth observation, communicate relaying and so on. To realize large distance transmission, we propose the use of available relay satellites as relay nodes. Accordingly, we apply software defined network (SDN) technology to ORS networks. We additionally propose a satellite network architecture refered to as the SDN-based ORS-Satellite (Sat) networking scheme (SDOS). To overcome the issures of node failures and dynamic topology changes of satellite networks, we combine centralized and distributed routing mechanisms and propose a fast recovery routing algorithm (FRA) for SDOS. In this routing method, we use centralized routing as the base mode.The distributed opportunistic routing starts when node failures or congestion occur. The performance of the proposed routing method was validated through extensive computer simulations.The results demonstrate that the method is effective in terms of resoving low end-to-end delay, jitter and packet drops.