• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.52-57
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• 1999

It is very important to design of QAM modulator of high spectral efficiency for high speed data transmission. In this paper, typical 16-QAM modulator is designed by modification design of DDFS(direct digital frequency synthesizer). DDFS generates sinusoidal waveform digitally to the frequency setting word. Phase modulation is accuratly made by control of a generated phase increment value and amplitude modulation is accomplished in the D/A converter output by control of amplitude level. For the suppression of harmonics and glitch, dual-structured DDFS is studied to improve the spurious characteristics. P-Spice is used for design and simulation in mixed mode. Also we can get the satisfactory results of designed 16-QAM modulator from the constellation output.

• The Transactions of the Korea Information Processing Society
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• v.3 no.5
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• pp.1187-1197
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• 1996

In this work, two-dimensional FIR digital filter is designed and simulated using research and educational CAD tools. The two-dimensional digital filter consists mainly of one-dimensional digital filter and line memory. To speed up one-dimensional digital filter, multiplications are carried out on the basis of hardwired-shifting methods by the digital filter coefficients represented in CSD formats, while carry-save adder and Manchester adder are used in addition. It is found that the designed digital filter operates up to 30 Mhz in VHDL simulation and operates normally in IRSIM simulation for the layout made by Berkeley CAD tools.

• The Journal of the Acoustical Society of Korea
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• v.16 no.2
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• pp.80-88
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• 1997

In this paper, the implementation of audio/data processor using ETRI DSP to support analog mode in digital/analog dual mode mobile phone is presented. Audio/data processor performs the wideband data processing, audio signal processing, demodulation function, and data rate conversion when it is operated in analog mode. These functions are programmed in assembly language, and then loaded to ETRI DSP together with vocoder program for the digital mode operation. This is a very efficient implementation of the dual mode cellular phone ASIC since the vocoder for the digital mode and audio/data processor for the analog mode are programmed together in the same hardware.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.3
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• pp.19-27
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• 1979

Microprocessor based digital filter was designed rising focus number system in order to increase the multiplication speed of microprocessor program. Addition and subtraction program was treated using look up table. The sampling speed was improved up to 500 samples per seconds on the third-order low- Pass digital filters.

• Journal of Industrial Technology
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• v.5
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• pp.27-36
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• 1985

마이크로 컴퓨터로 실현(實現)되는 디지탈 필터는 유한어장효과(有限語張效果)에 기인(基因)한 양자화(量子化)(quantization)와 잉여현상(overflow) 때문에, 이상적(理想的)인 선형(線型)필터도 비선형(非線型) 특성(特性)을 나타내어 Limit Cycle과 같은 오차의 원인이 된다. 본(本) 논문(論文)에서는 수학행렬(行列)의 안정(安定)성질을 이용한 Norm-Lyapunov 함수를 이용하여, 디지탈 필터의 안정도를 해석하였다. 잉여현상이 없는 경우에는 Jury-Lee 판별법을 적용하여 전자(前者)와 비교하였다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.3
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• pp.48-53
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• 1985

A real time digital subtraction angiographic system (RTDSA) was developed and utilized for diagnosis of the diseases related with the blood vessel conditions in 200 patients. In this paper, we present the system configurations and the real time processed images of the patients'abdominal, renal, femoral, and hepatic arteries.

• Review of KIISC
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• v.5 no.4
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• pp.5-13
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• 1995

본 논문에서는 디지탈 이동통신 시스템을 위해 제시된 기존의 세션 키 분배 및 가입자 인증 프로토콜을 소개하고, 선형대수에 기반을 둔 새로운 프로토콜의 제안 및 이의 안전성을 분석한다. 기존의 제안된 프로토콜이 단말기의 하드웨어적 제약성을 고려하여 작은 지수를 이용하는 RSA시스템이나 Modular Squqres Root 기법을 공개키 암호 체계에 기반을 둔 유한 체 상의 행렬과 벡터의 곱 계산이라는 측면에서 디지탈 이동통신 시스템에 적합한 방식이다.

• 전기의세계
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• v.16 no.3
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• pp.9-15
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• 1967

현금까지 R.I.스칸닝은 방사선검출기에서 얻어지는 디지탈신호를 계수율계를 통하여 아날로그 신호화하므로써 기록제어를 하고 있는데, 본 연구에 있어서는 디지탈신호를 아날로그 신호화하는 보고의 변환과정에 있어서, 정보원리상 정보손실이 불가변하며 실지로 계수율계의 시정수에 의한 시지연이 해상력에 큰 악영향을 미침에 착안하여, 검출기에서 얻어지는 디지탈신호를 정보변환을 하지 않고 그대로 이용한 디지탈제어에 의해서 기록방식을 개발하였다. 이로써 해상력의 향상과 아울러 기록동작을 순정자식화하여, 기록기구의 간소화와 경제화를 이룩하였다. 본 논문은 정보이론을 기초로하여 이론을 전관하고, 기록제어에 있어서의 최적조건을 제시하였으며, 이에 입각하여 설계시작한 색기록(Color Scanning)과 다중기록을 동시에 할 수 있는 개발된 R.I. Scanning의 설계내용과 그 시험결과를 제시하였다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.1
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• pp.27-36
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• 1983

The 12-Channe1 TDM/FDM translator is proposed which uses a periodically varying digital filter and the multiplexing weaver modulators. The general 12-Channel TDM/FDM translator using the Weaver modulators requires 24 interpolating FIR(finite impulse response) filters and 24 sinusoidal modulators, however the TDM/FDM translator proposed in this paper consists of one interpolating periodically varying digital filter and 12 sinusoidal modulators. The results obtained in this paper show that the system is simplified and the computation time is reduced. These facts are verified by the computer simulation.

• Economic and Environmental Geology
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• v.20 no.2
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• pp.119-123
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• 1987

Hankel transform of order 0 can be represented by a combination of Abel transform and Fourier transform. This Abel-Fourier method can offer computational advantages over a conventional digital linear filter method through the uses of a rapid Abel transform with shift variant recursive filter and of a fast Fourier transform. The Abel-Fourier method, however, is generally less accurate than a well-designed digital linear filter method. In geoelectrical applications, the digital linear filter method seems to be more flexible than the Abel-Fourier method.