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최적화 방법에 의한 칼라 TV용 SAW IF 필터의 설계에 관한 연구
황금찬,박용서,최영호 연세대학교 산업기술연구소 1984 논문집 Vol.16 No.1
In this paper, SAW IF filter for NTSC Color TV is designed by optimization technique using nonlinear programming. To carry out optimization, Fletcher Reeves algorithm is adopted, and objective function and its gradient are calculated by FFT algorithm. The band-pass filter function is translated down to the baseband before optimization and 58 variables are chosen for optimization. The electrodes consist of one eighth and five eighths wavelength fingers. The finger length of the uniform IDT is designed as 1.33 times as the maximum finger length of the uniform IDT is designed as 1.33 times as the maximum finger length of the apodized IDT. In experiment, SAW IF filter is fabricated on 128 ˚Y cut X LiNbO₃ substrate to suppress the spurious signals. The experimental results have shown close consistancy with given specifications.
코인시던스 기법을 이용한 DS/SS 패킷 라디오의 초기 동기에 관한 연구
이동욱,황금찬,박병창 연세대학교 산업기술연구소 1991 논문집 Vol.23 No.1
Constant false alarm rate (CFAR) is generally used in the threshold control method for spread spectrum packet radio. In this paper, coincidence technique is adopted for acquisition system to improve the defects of the CFAR mentioned above. For the performance analysis of this acquisition system, packet loss probability is calculated using blocking probability. From numerical results, it is found that the proper number of coincidences is seven, and dynamic SNR range in increased by 20 dB in comparison with that of the non-coincidence system.
정관수,황금찬,황인갑 연세대학교 산업기술연구소 1984 논문집 Vol.16 No.1
In this paper the design and fabrication of SAW resonator which could be used as a narrow-band pass filter and its characteristics are studied. The reflector of SAW resonator is designed to be resonated at 69.76㎒ by arraying the 150 metal electrodes of 12.5 ㎛ width which give 99.7% reflection coefficient, and the out put IDT's are designed at 69.7 MHΖto detect the stored energy between refctors. A SAW resonator is fabricated by depositing A1 on the surface of YZ-LiNbO₃which is piezoelectrics using photolithographic method, and it is shown that the resonant frequency of fabricated SAW resonator was obtained at 68.76 MHΖ approximately closed to the theoretical resonant frequency.
최영호,정관수,황금찬 연세대학교 산업기술연구소 1983 논문집 Vol.15 No.2
In this paper, a stabilized oscillator is realized using a radio frequency amplifier and a SAW delay line which is fabricated on YZ-LiNbO₃by photolithography. A multimode oscillation around 50 MHz and a single mode oscillation at 50 MHz are obtained within the frequency range of the frequency response of SAW delay line.
전력선 채널에서의 DS/SSMA BPSK 코릴레이션 수신기 성능에 관한 연구
강병권,조창길,조관,이재경,황금찬,Kang, Byeong-Kwon,Cho, Chang-Gil,Cho, Kwan,Lee, Jae-Kyeong,Whang, Keum-Chan 한국통신학회 1992 韓國通信學會論文誌 Vol.17 No.9
본 논문에서는 전력선 채널에서 DS/SSMA BPSK 통신 시스템의 전형 및 하드리미팅 상관 수신기의 성능을 분석하였다. Chan의 잡음 모델을 이용하여 전력전에서 발생하는 강한 임펄스성 잡음을 배경 잡음에 대한 임펄스성 잡음의 전력 스펙트럼 밀도비 $(N_1/N_b)$, 데이터 폭에 대한 임펄스성 잡음 폭의 비(f). 임펄스성 잡음의 발생주기에 대한 임펄스 잡음 폭 (DF)등의 파라미터로 모델링하여, 각 파라미터 변화에 따른 시스템의 성능을 분석하고, 다중접속 간섭 잡음을 가우시안 근사화하여 각 수신기의 다중접속 능력을 평가하였다. 분석 결과 $N_1/N_b$가 작고 f가 1에 가까운 경우 전형 상관 수신기의 성능이 더 우수했으나, $N_1/N_b$가 증가함에 따라 하드리미팅 상관 수신기가 비트 오율 및 다중 접속 능력면에서 전형 상관 수신기보다 더 우수한 성능을 나타냈다. In this paper, the performance of linear and hard-limiting correlation receivers for DS/SSMA BPSK power line communication system is analyzed. Strong impulsive noise of power line is modeled with Chan's noise model, and the performance of both receivers is analyzed in terms of parameters such as ratio of power spectrum density of impulsive noise to that background noise, ratio in impulsive noise width th that of data bit, and interarrival time of impulsive noise. And also multiple access capacity is evaluated with Gaussian approximation of multiple access interference. The results of this analysis reveal that the performance of linear correlation receiver is superior to that of hard-limiting correlation receiver when $N_1/N_b$ is small and is close to 1. But the BER and the multiple access capacity of hard-limiting correlation receiver becomes better in comparison with linear correlation receiver as $N_1/N_b$ increases.
Optical Image Scanning Using P-N Diode Memory Correlator
Whang,Keum-Chan 연세대학교 산업기술연구소 1981 논문집 Vol.13 No.1
An acoustic scanning principle of an optical image using SAW p-n diode memory correlator is described. The illumination modulates the envelope of charge grating acoustically stored in a p-n diode array. One narrow acoustic scanning pulse reads out the stored charge grating envelope modulated by illumination. Due to the time integration effect of photon, this technique shows higher sensitivity than convolver techniques.
포토리토그라피 방법에 의한 彈性表面波 遲延線의 제작에 關한 硏究
황금찬,박창엽,나관영 연세대학교 산업기술연구소 1981 논문집 Vol.13 No.2
A fabrication method of surface acoustic wave delay line was studied. An optimal interdigital transducer at center frequency 50 (MHz) for YZ-LiNbO₃was designed, and deposited by means of photolithography and vacuum evaporation. Approximately 7.5 (microsec) delay time was obtained by applying truncated 50 (MHz) input signal. Total loss of the delay line was approximately 14 (dB) at 50 (MHz) and agreed with theoretical loss of the device.
SAW 소자를 이용한 국산 칼라 TV IF 필터의 개선에 관한 연구
김동윤,황인갑,황금찬 연세대학교 산업기술연구소 1982 논문집 Vol.14 No.2
In this research, the possibility of development of SAW filter for the color TV IF filter of the NTSC system which is used in Korea, is studied. Since SAW filter consists of transmitting and receiving IDT's deposited on the surface of piezoelectric substrate and the frequency response of SAW filter related directly to the time response via the Fourier transform, the frequency response of SAW filter is determined from the impulse response of IDT's. The impulse response of SAW filter is obtained by computer simulation using building block method from the frequency response of NTSC color TV IF filter and the geometrical structure of IDT of SAW filter is designed from the obtained impulse response. SAW filter for NTSC color TV IF filter is fabricated by depositing Al on the surface of YZ-LiNbO₃substrate using photolithographic method and it is observed that the frequency response of the fabricated SAW filter is approximately close to the NTSC color TV IF filter specifications and this study has shown the possibility of development and production of small, rugged, electronic power saving and tuning free SAW filter for domestic color TV IF filter.