• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.520-523
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• 2009

The drive towards lowering costs and increasing frame rates results in new panel designs and thereby new photomasks designs. One common way to reduce cost is to reduce the number of production steps. For this multi tone photomasks (MTM) are needed. MTMs contain more information and increases photomask placement requirements. Increasing frame rates lead to shrinking geometries. The combination of HTM and shrinking geometries drastically increases the requirements imposed on the pattern generators used to print the photomasks. New methods are therefore needed to enable future photomask manufacturing. This paper introduces three advanced image quality enhancing methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2C
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• pp.217-225
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• 2009

Tone injection scheme has been known as one of peak to average power ratio (PAPR) reduction methods deployable to multi-carrier system like orthogonal frequency division multiplexing (OFDM). The basic idea in tone injection scheme is to enforce the constellation size larger so that each of original constellation points is mapped into the preassigned distinct locations. According to the tone injection scheme, it increases symbol power highly induced inherently by expanding constellation to get optimal PAPR reduction. In the other hand, to get optimal power increase, the PAPR would be reduced insufficiently with limited tone injection signal. To withstand these problems, this paper consider the reduction of the PAPR and power increase problem simultaneously, Toward this, the tone injection scheme accomplished by employing the weighted sum genetic algorithm which has been utilized to solve multi-objective optimization problem (MOOP). The simulation results verifies that the proposed scheme can control the effective PAPR performance and alleviation of power increase flexibly by the weight value at the expense of relatively low complexity.

• ETRI Journal
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• v.38 no.6
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• pp.1124-1134
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• 2016

The tone reservation method is one of the most effective pre-distortion methods for peak-to-average power ratio reduction in orthogonal frequency division multiplexing (OFDM) systems. Its direct application to OFDM systems with offset quadrature amplitude modulation (OQAM) is, however, not effective. In this paper, two novel TR-based methods are proposed, specifically designed for OFDM/OQAM systems by taking into consideration the overlapping nature of OQAM signals. These two methods have different approaches to the generation of the peak-cancelling signal. The first one (overlapped scaling tone reservation) generates the peak-cancelling signal using a least squares approximation algorithm with possible adjacent symbol overlap; the second one (multi-kernel tone reservation) generates the peak-cancelling signal by using multiple impulse-like time domain kernels. It is shown by simulation that, when used in OFDM/OQAM systems, the proposed methods can provide better performance than the direct application of the existing controlled clipping tone reservation method, and even outperform the multi-block tone reservation method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.10
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• pp.797-810
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• 1990

The error rate equations of digitally modulated signals transmitted through the Gaussian noise and tone multiple interference channel have been derived. Using the derived equations of error probabilities in the environments of Gaussian noise tone interferer and Gaussian noise multiple interferer, the error rate performances of various digitally modulated signals have been evaluated, and compared in graphs as a function of average carrier to tone interferer power ratio(CIR), average carrier to multiple interferer power ratio(CIT) and the average carrer-to-Gaussian noise powr ratio(CIR). In this paper, the modulation schemes such as amplitude shift keying (ASK), phase shift keying(PSK), frequency shift keying(FSK), minimum shift keying(MSK), quadrature amplitud modulation(QAM) and amplitude phase shift keying(APK) have been selected for the study of performance comparison. The results of comparison show us that, in low bits/sec/Hz, PSK is superior to the other schemes, but in high bits/sec/Hz, mixed multi ary type is better than single multi ary type. And in strong noise evironment, the multiple interferer has much influence than tone interferer, however, in low noise environment. the mojor error factor is tone interferer. But tone interference effect nearly disappears over specified CIR level about 20[dB]. And the modulation schemes using amplitude are heavily influenced by multiple interference.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.100-106
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• 2007

In this paper, the performance of OFDM(Orthogonal Frequency Division Multiplexing) and FMT(Filtered Multi-tone) Systems is compared under jamming environment. Two systems are multi-carrier systems to improve data rates. Through the comparison of two systems under jamming environment, the characteristics and strong/weak points of each system are analyzed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.116-121
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• 2016

In Internet of things (IoT) area, researches on recognizing human emotion are increasing recently. Generally, multi-modal features like facial images, bio-signals and voice signals are used for the emotion recognition. Among the multi-modal features, voice signals are the most convenient for acquisition. This paper proposes an emotion recognition method using tone and tempo based on voice. For this, we make voice databases from broadcasting media contents. Emotion recognition tests are carried out by extracted tone and tempo features from the voice databases. The result shows noticeable improvement of accuracy in comparison to conventional methods using only pitch.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1846-1863
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• 2016

High dynamic range (HDR) images can present the perfect real scene and rich color information. A commonly encountered problem in practical applications is how to well visualize HDR images on standard display devices. In this paper, we propose a multi-scale decomposition method using guided filtering for HDR image tone mapping. In our algorithm, HDR images are directly decomposed into three layers：base layer, coarse scale detail layer and fine detail layer. We propose an effective function to compress the base layer and the coarse scale detail layer. An adaptive function is also proposed for detail adjustment. Experimental results show that the proposed algorithm effectively accomplishes dynamic range compression and maintains good global contrast as well as local contrast. It also presents more image details and keeps high color saturation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1172-1175
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• 2011

In this paper, a design method of multi-tone signals for the measurement of adjacent-channel power-ratios on power amplifiers is suggested. Because most tests for power amplifiers in production are performed with single-tone signals, its testing accuracy is not guaranteed as the signal complexity increases. Therefore, the application of multi-tone signals to the testing is suggested by optimized complex coefficients of each tones for the best statistical similarity to the original modulated signal. From the verification, a 802.11a signal was replaced with a multi-tone signal of N=10, with the complex coefficients generated by the suggested method. The resulting measurements on the ACLR of 2.4 GHz power amplifier showed successful accuracy of less than 1 dB discrepancy.

• Journal of Broadcast Engineering
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• v.4 no.1
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• pp.1-11
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• 1999

This paper introduces orthogonally multiplexed modulation and demodulation methods based on Wavelet Packet Bases and particularly describes Wavelet Packet Modulation (WPM) techniques that provide the designer of transmission signal set in time-frequency domain with tree structural information which can be adapted to given channel characterristics. Multi-dimensional signaling methods are also contrasted to common and different characteristics of conventional QAM. multi-tone modulation methods. The paper addresses the mothod how to find a best tree structure that has more adaptivity to impulse and narrowband tone pulse noises using a tunning algorithm which arbitrarily partitions the time-frequency space and makes a suitable orthogonal signaling waveforms. Simulation results exhibits a favorable performance over existing mod/demod methods specially for narrowband tone pulse and impulse interferences.

• The Journal of the Acoustical Society of Korea
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• v.22 no.4
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• pp.276-285
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• 2003

In this paper, we present real-time implementation of a R2MFC/DTMF (R2 Multi Frequency Combinations/Dual Tone Multiple Frequency) tone receiver/sender using a high performance DSP (Digital Signal Processor) and apply it to a carrier class VoIP (Voice over Internet Protocol) gateway system. The Receiver utilizes the Goertzel filter and the sender adopts the harmonic resonant filter. We describe, in detail, the techniques of multi-channel real-time implementation on a Texas Instruments TMS320C62x DSP such as effective PCM (Pulse Code Modulation) in/out by means of DMA (Direct Memory Access) and McBSP (Multi Channel Buffered Serial Port) and message communication via HPI (Host Port Interface), etc. From experimental results, we confirmed that the optimized code provided 780 channel capacity at 250㎒ C6202, and the our R2MFC/DTMF receiver/sender met ITU-T (International Telecommunication Union-Telecommunication) specifications.