• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.9 no.1
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• pp.29-34
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• 2010

In this study, we realized the broadband home gateway system of dual mode based upon EDR 2~3Mbps transmission speed and 300Mbps of 802.11n, In broadcasting and telecommunication convergence networks to deliver multimedia services, high-quality home. The bluetooth module is designed to use general low rate data speed service and the 802.11n module also is designed to use high rate speed service at various home network situation. The dual mode home gateway system, bluetooth and 802.l1n module, is well realized for many specification such as emission power, spurious power, impedance matching, frequency channel test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.11
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• pp.801-807
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• 2022

In this paper, we propose an ultra compact S-Band PCM/FM telemetry transmitter. The equipment is compact, so it can be applied to a limited space and capable of stable data transmission was designed and manufactured even with specifications set differently for each operating environment and system. RF direct conversion structure is used for the miniaturization of equipment, an RF transmission board, Power distribution board, and a signal processing board were implemented on a single PCB, so that the function of the transmitter could be performed with a minimum device. According to the target specification, variable output of 1~10W and variable data rate of 390kbps~12.5Mbps is possible in S-Band(2,200~2,400MHz) without degradation of performance. To verify the performance of the equipment, the RF performance test and BER measurement test were performed after the equipment was manufactured. It was confirmed that the OBW, null-to-null bandwidth, 1st IMD, Spurious emission, Phase noise specification of the PCM/FM modulated signal which is presented by the IRIG standard were satisfied, and we can confirm the data received using the transmitter inspection equipment were transmitted normally without distortion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2249-2253
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• 2011

This paper analyzed the problems of the Korean output regulation in the relevant band through an analytic comparison of the current trend of each country and their standard values concerning the technical standard of low power u-IT equipments. In connection with the standard value of technical values of each country, which has been proposed in the registration of the appropriate electric wave, the paper aims to propose the standard value that could actually be introduced for suitable low power u-IT installations in Korea. Provided that the Korean standard may be upgraded based on the tolerances of technical standards proposed in this paper, this is expected to be committed to the distribution and advancement of low power u-IT equipments; and further, it is anticipated to be prepared with competitiveness not only in the Korean communications market, but also in the international communications market.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.1 no.1
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• pp.23-31
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• 1976

When Television signal of VHF and UHF channel is retransmitted at the relay system with 6MHz Bandwidth including video and aural signals, the image is often affected with the unnatural changes of output amplitude frequency response within ttle region of dual sideband near to the carrier frequency. These phenomena are caused by the unnecessary lower sideband due to the spurious emission at the local oscillator, the nonlinear distortion in the linear amplifier, the intermoudulation distortion with the components of neighboring signal, the AM-PM conversion, and the envelope delay distortion. From the output characteristics, considering above results, the chief cause is caused by nonlinear response and has an effect on the bias states. Finally, it is confirmed that the effects on neighboring signal appear high in case of Down conversion than Up conversion and obtained the method for reducing the effects on the system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.1
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• pp.61-72
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• 1997

The implementation of base station transceiver for Wideband CDMA(Code Division Multiple Access) PCS(Personal Communication Service) system using spread spectrum CDMA technology is presented in this paper. The receiver that requires wide dynamic range and high sensitivity and the transmitter that has good spurious emission supression were designed and implemented with 5 MHz RF channel bandwidth. This paper shows the some factors that should be considered and simulated using the RF simulation S/W with commercial and customized components. The implemented transceiver based on the simulation gave good results that satisfied the functional specifications of the transceiver.

• Journal of IKEEE
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• v.25 no.1
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• pp.53-63
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• 2021

As the types of radio equipment becomes more complex and diversified in various fields, radio interference occurs frequently. In the domestic situation where the territory is narrow, many systems are deployed in a specific highland with a good radio wave environment. Radar systems that transmit high power signals of the same band are sometimes deployed and operating at close distance. In this paper, the type of interference was classified for the actual radio wave interference phenomenon and appropriate signal interference parameters were derived. The power density of the interference signal was predicted using the analysis method and the effectiveness was verified through measurement. And, we propose a method to minimize interference by analyzing operating scenarios of interferer radar and victim radar.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1011-1016
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• 2003

In this paper, we investigate the relationship between the intermodulation signal of 2-tone and CDMA spurious emission of HPA. And confirm that the fifth IMD signal of HPA has more important effect upon CDMA ACPR characteristics than the third IMD signal. We present the method for the power amplifier to satisfy the 2-tone and CDMA specification simultaneously, and that is to use the predistorter for improving the third IMD signal of 2-tone for the power amplifier which is tuned to satisfy the CDMA specification and not to satisfy the 2-tone specification. The result by using the method which is presented from this paper shows that the ACPR is improved about 2 dB for CDMA 1FA(frequency allocation) signal and the third IMD signal is improved about 20 dB for CW 2-tone signals and we confirmed the specification is satisfied simultaneously.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.268-275
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• 1999

In this paper, a new type of linearization technique proposed, in which the predistortor was added to the feedforward linearizer. As the input power level is applied to HPA, the gain and phase characteristics of the amplifier are also varied. By using of the predistorter the amplitude imbalance and phase imbalance is kept constant. Experimental results are present for Korea PCS frequency band. The center frequency of the feedforward amplifier is 1.843.75 MHz with 1.23 MHz bandwidth. The 2-tone intermodulation distortion at 37dBm output power is about -50dBc, and spurious emission are -46dBc at $fc{\pm}\;885KHz\;and\;-52dBc\;at\;fc\;{\pm}1.98MHz$, respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.229-236
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• 2022

This article studied the radio station inspection method, which utilizes the 8T8R combiner to reduce 5G radio station inspection measurement times. It is a common that 5G radio station inspections measure RF (Radio Frequency) output signals, which correspond to the number of arrayed antennas individually. However, this study suggested a way to save the time spent on existing methods, by comparing measurement values of individual channels and 8T8R. As a result, it is confirmed that when the 8T8R combiner is used, not only the resulting value of radio station inspections was accurate, but also the measurement time being shortened by up to 8 times compared to existing method.