• MALSORI
• /
• no.65
• /
• pp.81-91
• /
• 2008

In this paper, we propose a new variable bit-rate speech coder based on the waveform interpolation concept. After the coder extracted all parameters, the amounts of the distortions between the current and the predicted parameters which are estimated by extrapolation using past two parameters are measured for all parameters. A parameter would not be transmitted unless the distortion exceeds the preset threshold. At the decoder side, the non-transmitted parameter is reconstructed by extrapolation with past two parameters used to synthesize signals. In this way, we can reduce 26% of the total bit rate while retaining the speech quality degradation below 0.1 PESQ score.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.12
• /
• pp.209-219
• /
• 1995

As a new algorithm for RC tree delay estimation, we propose a $\tau$-model of the driver and a moment propagation method. The $\tau$-model represents the driver as a Thevenin equivalent circuit which has a one-time-constant voltage source and a linear resistor. The new driver model estimates the input voltage waveform applied to the RC more accurately than the k-factor model or the 2-piece waveform model. Compared with Elmore method, which is a lst-order approximation, the moment propagation method, which uses $\pi$-model loads to calculate the moments of the voltage waveform on each node of RC trees, gives more accurate results by performing higher-order approximations with the same simple tree walking algorithm. In addition, for the instability problem which is common to all the approximation methods using the moment matching technique, we propose a heuristic method which guarantees a stable and accureate 2nd order approximation. The proposed driver model and the moment propagation method give an accureacy close to SPICE results and more than 1000 times speedup over circuit level simulations for RC trees and FPGA interconnects in which the interconnect delay is dominant.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1636-1639
• /
• 2002

We proposed the new reset waveform for reducing reset period. The square pulse is applied to the address electrode when the ramp pulse increases before a discharge occurs between sustain electrodes. If the discharge occurs between address electrode and X electrode, the wall charge is reversely accumulated between sustain electrodes compared with the applying voltage before the discharge occurs between sustain electrodes. So the next discharge more weakly occurs between sustain electrodes. If the more weak discharge is obtained, it can make the low background luminance and the high contrast ratio and reduce ramp up time in the ramp reset waveform.

• The Journal of the Acoustical Society of Korea
• /
• v.11 no.4
• /
• pp.14-21
• /
• 1992

The waveform coding is concerned with simply preserving the wave shape of speech signal through a redundancy reduction process. In area of the speech synthesis, the waveform codings with high quality are mainly used to the synthesis by analysis. However, because the parameters of this coding are not classified as either excitation parameters and vocal tract parameters, it is difficult to applying the waveform coding to the synthesis by rule. In this paper, we proposed a new pitch alternation method that can change the pitch periods in the waveform coding by using the cepstrum analysis. Thus, it is possible that the waveform coding is carried out the synthesis by rule in speech processing.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.6
• /
• pp.661-670
• /
• 2013

In this paper, we propose the measurement techniques of mixed waveform. Mixed waveform has phase-continuous periodic waveform with fixed frequency signal and Linear Frequency Modulation(LFM) signal. This waveform is generated from a compact radar transmitter with frequency synthesizer and high power amplifier. Frequency synthesizer generates various signal waveform with continuos phase and high power amplifier amplify transmitting signal. First, we describe a compact radar transmitter with the phase-continuos signal and then verify the distortion characteristic of pulse compression by the mismatch of LFM waveform. Second, we describe three kinds of measurement techniques for measuring LFM waveform. These techniques include methods using signal analyzer, signal source analyzer and new methods using RF mixer and phase shifter. Finally, we verify the accuracy of the measurement technique from the pulse compression result of receiving signal.

• Journal of the Korean Geotechnical Society
• /
• v.32 no.10
• /
• pp.67-79
• /
• 2016

Waveform micropile is an advanced construction method that combined the concept of conventional micropile with jet grouting method. This new form of micropile was developed to improve frictional resistance, which consequently leads to achieving higher bearing capacity and cost efficiency. Two field tests were conducted to examine the field applicability as well as to verify the effects of bearing capacity enhancement. In particular, waveform micropile construction using jet grouting method was performed to evaluate the viability of waveform micropile installation. After testing, the surrounding ground was excavated to check the accomplishment on the shape of waveform micropile. The result showed that waveform micropile can be installed by adjusting the grouting time and pressure. In the loading tests, waveform micropile's bearing capacity increased by 1.4 to 2.3 times depending on their shapes when compared with conventional micropile. Overall results clearly demonstrated that waveform micropile is an enhanced construction method that can improve bearing capacity.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.1
• /
• pp.142-155
• /
• 2016

In order to satisfy 5th generation mobile system's requirements, recently many works have been done in various layers. Especially in physical layer, new waveforms like Filter bank Multi-Carrier(FBMC), Universal Filtered Multi-Carrier(UFMC), Generalized Frequency Division Multiplexing(GFDM) have been proposed and their performance have been evaluated. But most previous researches have provided limited information by comparing couple new waveforms each other with different assumptions and simulation parameters. In this paper, we investigate the key technique of each 5G new waveform, and compare them in various aspects and the same simulation environment, and finally provide what waveform is appropriate in different application scenarios.

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.607-610
• /
• 1998

The major objectives of speech coding include high compression ratio for transmission in the band limited channel, high synthesized speech quality in terms of the intelligibility and the naturalness and fast processing speed. In general, speech coding methods are classified into the following three categories: the wavelform coding, the source coding and the hybird coding. In this paper, we proposed a new waveform coding method using PSOLA(pitch-synchronous overlap add) technique. First, we fixed one basic waveform per pitch and measured the formant similarity between basic and neighbor waveform. Second, if the similairy satisfied threshold values, we compress the neighbor waveform per pitch and then store or transmit. When the comparession is about 45%, we obtained about 4 in MOS.

• Journal of the Korea Society for Simulation
• /
• v.10 no.1
• /
• pp.25-34
• /
• 2001

In this paper, we describe the generation method of interface logic which replace between IP & IP handshaking signal with asynchronous logic circuit. Especially, we suggest the new asynchronous sequential "Waveform to VHDL" code creation algorithm by flow chart conversion : Wave2VHDL - if only mixed asynchronous timing waveform is presented the level type input and pulse type input for handshaking, we convert waveform to flowchart and then replace with VHDL code according to converted flowchart. Also, we confirmed that asynchronous electronic circuits are created by applying extracted VHDL source code from suggest algorithm to conventional domestic/abroad CAD Tool, Finally, we assured the simulation result and the suggest timing diagram are identical.

• Journal of Welding and Joining
• /
• v.19 no.6
• /
• pp.643-651
• /
• 2001

A new waveform control technique has been developed for suppressing the spatter generation in the repelled transfer mode of high current $CO_2$ welding. Based on the spatters in repelled transfer, a waveform concept of concept was established in a way to drop the welding current to lower level right before the pendant weld drop detatchment so that the explosion force associating with drop detatchment was decreased. There were several variables to be controlled such as the moment of current drop, the base current and the time of retention at the base current. Either at lower base current or at longer retention time, the more instantaneous shot circuits were int개duced and thus the spatter generation rates were increased. With optimizing the control variables, the amount of spatter generated was decreased by about 30%.