• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.87-96
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• 2012

In this research, we describe recent technologies and system requirements of the passive microwave radiometer used in Earth observation satellites. And we classify types of microwave radiometer system for Earth observation satellites according to observation targets and ways to scan and discuss a design method. Also, requirements of passive radiometer for Earth observation missions in the latest practical examples used and developed are analyzed in this research.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.87-93
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• 2019

We discuss the design of a radiometer using a millimeterwave(Ka-band) seeker. We applied a total power radiometer, thus the radiometer is composed of a IF-drive amp, band-pass filter, detector and an Op-amp additionally. As a radiometer measure a radiated signal of an object which is noise-like, a radiometer is easily affected by the variance of system temperature. To mitigate an adverse effect, we propose a compensation method in a radiometer without brightmess temperature compensation circuits. Through some experiments such like a distinction a target and the background, we have verified that the designed radiometer system has distingushed a car from the ground completely.

• Journal of Broadcast Engineering
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• v.17 no.6
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• pp.990-1003
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• 2012

In this paper, the possibility and necessity of the digital broadcasting propulsion in AM and FM is presented based on DRM and DRM+ transmission modes, They are the members of series technological family in digital radio development. As the frequency utilization, the application of DRM+ is flexible in any mode such as IN-BAND or OUT-OF-BAND. When the digital audio broadcasting is planned at LOW-VHF bandwidth such as TV channel No.5 and NO.6 being adjacent to FM band and OUT-Of-BAND DRM+ technology is applied, there is no collision and jamming. Particularly, in the IN-BAND Hybrid mode, it is mentioned that there was the difficulty problem for multiple SFN transmitters uses. Not like the IN-BAND mode the OUT-OF-BAND mode lets multiple transmitters, because neighbor transmitters do not interfere each other. Digital transmitter can be combined with the existing FM transmitter. The intensity of power and size of area can be easily determined according to local broadcasters' condition. And the OUT-OF-BAND mode is advantageous for AM/FM integration in digital radio receiver manufacturing, which makes the conversion schedule much shorter.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.163-167
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• 2016

We have developed a millimeter-wave radiometer system for applications in the fields of medical imaging. In this paper, we introduced the brightness temperature measurement in the human body using Millimeter-wave Radiometer. Calibration of sensitivity of the radiometer system is essential to measure equivalent temperature (brightness temperature) of objects. We have developed, as a calibration source, a new type of black body for the millimeter wave region with temperature control capability. The system noise figure and temperature sensitivity of the system measured using the blackbody are 3.3 dB and 0.1 K, respectively. The brightness temperature of human body through clothes was measured to be around $38^{\circ}$[C].

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.1013-1022
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• 2010

In this paper, we propose a C-band radiometer for remote sensing of land surface temperature and present its experiment results using asphalt as target. Total power type is selected for high sensitivity and low power consumption, super-heterodyne type is selected for stable high gain. A radiometer designed at 5.1 GHz to have operating bandwidth of 110 MHz has system gain of 59 dB, noise figure of 2.7 dB and receiving sensitivity of 0.45 K. We have measured surface temperature on asphalt by using implemented system and thermometer. Analysis data of each measurement results show that a radiometer operates linearly with output voltage variation rate of 6 $mV/^{\circ}C$. As a result, we verified validity of a developed C-band radiometer for remote sensing of land surface temperature.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11A
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• pp.1059-1065
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• 2010

Recently, analog broadcasting are being converted into digital radio broadcasts, Among the various ways that HD Radio is a candidate for the U.S. approach, Digital Radio will transmit a digital signal to existing analog FM/AM. It provides clear sound quality, traffic information, weather information and various value-added services. In addition, the converted digital radio will be able to meet demand to growing demand for analog FM. In this paper, Digital FM Radio system in the same frequency band using electric field strength of the received digital radio broadcasting interference effects were analyzed. And Digital FM Radio Receiver interference effects were analyzed by interference signal power and signal power. Results were confirmed by applying equation at minimum field strength and SNR.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.149-158
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• 2007

A In the rapidly changing media environment, radio needs to be digitized in order to provide regular compatible service. Especially, most medium high frequency Medias have program contents thar are similar to the standard FM bandwidth, so digitizing radio will bring less effect than it is expected. However, the characteristics of radio medias are mobility, individuality, site-to-site, wide service coverage, immediate delivery and publicity, so it is necessary to study the future of radio media to provide continuous services, moreover, the main discussion regarding balanced development between medias will be the trend of the digitization of radio. Also it is easy and will cost less to change compared to other medias. AM was the first media to broadcast in Korea, and its network is spread all over Korea, also the receivers are the most widely distributed which means the signal reaches everywhere in Korea. In this study, the proper service model for AM digital radio is provided in this environment in which all Medias are rapidly digitizing due to the advancement of digital technology. The results of experimental are based on library study and KBS data of sound wave.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.1
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• pp.58-71
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• 2019

This paper proposes architecture of a cognitive radio engine platform and the allowable frequency channel reasoning method that enables acquisition of the allowable channels for the military tactical network environment. The current military tactical wireless communication system is increasing need to secure a supplementary radio frequency to ensure that multiple wireless networks for different military wireless devices coexist, so that tactical wireless communication between the same or different systems can be operated effectively. This paper presents the allowable frequency channel reasoning method based on cognitive radio engine for realizing DSA(Dynamic Spectrum Access) as an optimal available frequency channel. To this end, a case-based allowable frequency channel reasoning method for cognitive radio devices is proposed through modeling of primary user's traffic status and calculation of channel occupancy probability. Also through the simulation of the performance analysis, changing rate of collision probability between the primary users' occupancy channel and the available channel acquisition information that can be used by the cognitive radio device was analysed.

• 한국노년학
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• v.30 no.4
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• pp.1329-1344
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• 2010

This study is intended to find out how production people have been creating senior radio program. For this purpose, the study set up the three research questions and employed in-depth interviews with ten production people: First, production people find out senior radio listeners who have been very royal attendance of the program for a long time. And they examined senior listeners prefer to listen about health care, information about elderly life and singing contest. They have been made para-social interaction with master of ceremonies (MC). Second, unlike other radio program, the senior radio program has concentrated on the radio station's image and public interest rather than financial profit and viewing rate. Normally, it was known that radio program for senior used carried on break of the day. But some program has been broadcasted on prime time in the afternoon. Target audience of senior radio program has been expanded over the forties and the fifties from sixties. Thirdly, in general the role of producer is critically important to produce program. However, MC and scriptwriter are far more experienced and specialized on the field than producer in radio program for senior.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.939-944
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• 2014

Traffic accidents caused by the attention dispersion are increasing and the behavior of the attention dispersion affects the front-observing rate, road keeping ability, and reaction time for a dangerous situation. Many drivers listen to a radio broadcast and they have to change the frequency for continuously listening a radio broadcast of the specific broadcasting station in case of crossing a boundary of the particular area. In this situation, the possibility of a car accident increases, because the attention dispersion of a driver might be occurred. Especially, the risk of a car accident caused by changing the frequency of a radio is more serious in the highway, due to the high speed of a vehicle. In order to reduce the risk of a car accident caused by handling a radio during driving car, in this paper, we propose an automatic frequency conversion algorithm for vehicle radio, which saves normal system frequencies of primary broadcasting stations in a database and determines new frequency of the changed area using the location information obtained from a navigation system in a boundary of the specific area. After determining new frequency, the proposed algorithm selects a frequency with better receiving rate comparing signal-to-noise ratios (SNRs) of two signals corresponding previous and new frequencies.