• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.116-122
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• 2024

In this paper, course structure and course width were studied among the main performances of the system to derive the required performance of the modulation index, output power, and phase change specifications of the instrument landing system (ILS) localizer power amplifier. To satisfy the course structure's deviation standard (± 5 uA), the difference in depth of modulation (DDM) deviation standard of the carrier with sideband (CSB) amplifier was standardized to ± 1 uA(0.001 DDM). CSB 30 W power amplifier was designed, and through the modulation compensation circuit, sum in depth of modulation (SDM) is 40% ± 0.1% and DDM is ± 0.0005 DDM in the operating output range(45 dBm ~ 35 dBm). In addition, the course width and displacement sensitivity specifications were analyzed through simulation, and the ± 0.1° change applied during comissioning inspection, which is the most stringent standard, was applied. The output variation of the suppressed with sideband only ( SBO) amplifier was ± 2 mW or less, The phase was standardized to within ± 3 ° and the characteristics were satisfied. By applying a compensation circuit according to output power and temperature, stable modulation index, output, and phase characteristics were obtained.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.6
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• pp.1058-1063
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• 2010

In this paper, we designed self-frequency synchronizing circuit using image rejection mixer(IRM) and single-sideband(SSB) up-converter which can effectively eliminate the image frequencies occurred in multi-channel super-heterodyne receivers and help us to match inter-channel phase. Also the self-frequency synchronizing circuit simplifies system because there need no extra devices for making intermediate frequency(IF) by creating the local signal within several nanoseconds by means of generating the same frequency of IF signal and modulating radio frequency(RF) signal. We adopt the limiting amplifier for the purpose of protecting the circuit from spurious signals which come from the front end side having wide instantaneous bandwidth characteristics and constantly injecting same level into the input local signal of IRM. The IRM we fabricated has image rejection ratio of 27dB, which is good over 7dB for foreign company's. Also, the SSB up-converter we fabricated has 1dB compression point of 18dBm, which is good over 16dB for foreign company's. And the size is compact about one-forth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2769-2774
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• 2010

In this paper, we have proposed sideband injection locking method, heterodyne technique, to generate millimeter-wave signal. Microwave signals in cellular broadband mobile communication networks and distributed networks can favorably be generated and distributed by optical techniques. In principle, these techniques have already been investigated for optical control of phase-array antennas, characterization of photo-detector and phase locking of millimeter-wave oscillators and now being applied to wireless communications. The generation and transmission of millimeter-wave radio signals by optical means is of interest for future pico-cell broadband mobile communication system, especially for systems operating at frequencies of tens of GHz applicable to LMDS. We experimented and analysed the generation of millimeter wave signal.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.195-196
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• 2008

A ring resonator based band-pass filter enabling enhanced sideband suppression was proposed and demonstrated. It is composed of a single-ring based-pass section combined with a band-rejection section based on two different coupled rings. As for the achieved device performance, bandwidth was reduced from 98 MHz to 48 MHz by about 51% with no remarkable excessive insertion loss as expected. And the quality factor of the device was increased by about 105%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.544-545
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• 2012

In recent years, vehicle manufacturers have steadily developed fuel saving technologies such as multi-speed automatic transmission. With such a background, the Hyundai-powertech have developed the new 6-speed rear wheel drive(RWD)automatic transmission for FR vehicles. Despite having six-speed, it has the same number of planetary gears as a previously used five-speed automatic transmission and fewer brakes and one-way clutches than the 5 A/T, meaning that it is light, compact, and inexpensive. But, in addition to meshing this internal and external gear simultaneously and phase difference by the tooth contact point and the time difference occurs asymmetric and symmetric sideband noise and vibration caused by the modulation in the vehicle. In this paper presents a method for the design of the carrier phase difference by developing various theories and experiments for gear noise.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.580-580
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• 2013

공정 플라즈마에서 사용할 수 없는 단일 랭뮤어 탐침법의 단점을 극복하기 위해서 부유 고조화파 탐침법이 개발되었고, 개선되어왔다. 다중 주파수를 인가하여 발생하는 고조화파 신호들 중 상호간섭주파수의 진폭을 이용하는 Sideband 방법과 원신호의 주파수 진폭을 이용하는 이중 주파수 방법이 있는데, 본 연구에서는 위와 같이 응용된 방법들과 기존의 부유 고조화파 탐침법의 장단점을 파악하고, 차이점을 규명하였다. 플라즈마 변수를 이끌어내기 위해 사용된 베셀함수의 민감도를 통해 특정 전자온도 영역에서의 각 방법들의 신뢰성을 비교해보았고, 측정값에서의 차이를 주파수 응답 특성 차이 및 전자 에너지 분포의 차이로 설명하였다. 이런 비교 연구를 통해 상황 별 적합한 측정 방법을 선택적 이용할 수 있을 뿐만 아니라, 이를 통해 측정하는 플라즈마 변수의 신뢰성을 향상시킬 수 있을 것으로 예상된다.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.570-572
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• 2008

The modulation quality of the I/Q modulator in a wireless transmitter usually affects system performance and it mostly depends on both a nonlinearity and a distortion, from the third order intermodulation($IM_3$) signal and the error components such as an input amplitude error and a local phase error, respectively. This paper focused on how much the Single Sideband Ratio(SSR), which indicates the signal distortion, changes according to the variation of the error components. Consequently, since a desired signal, side band signal at the I/Q modulator output are also represented with those power series coefficients and the error components, the effects of the error components on SSR to meet the EVM specification of the WPAN can be clearly analyzed.

• Proceedings of the Optical Society of Korea Conference
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• 1999.08a
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• pp.96-97
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• 1999

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1380-1386
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• 2016

In this paper, we propose and evaluate OFDM(Orthogonal Frequency Division Multiplexing)-SSB(Singe Side Band) for improving spectral efficiency. The proposed system is based on OFDM system using DCT(Discrete Cosine Transform) and DHT(Discrete Hilbert Transform) for SSB modulation, this proposed system transmit a BPSK modulation signal through a single sideband and BPSK modulation signal through the other single sideband. In other words, we design and evaluate the proposed system which transmit two BPSK signal through each other single sideband. Also each BPSK BER performance is similar with theoretical BPSK BER performance. the proposed system transmits BPSK signal using half of spectrum of conventional OFDM system or transmit two BPSK signal in same time.

• Bulletin of the Korean Space Science Society
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• 1995.04a
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• pp.19-19
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• 1995

No Abstract. See Full-text