PSPICE Macromodeling에 의한 PLL의 주파수 특성연구

鄭天錫,朴明烈,金世烈,金洪九 울산대학교 1996 공학연구논문집 Vol.27 No.2

본 논문은 범용화되어있는 Microsim 사의 PSPICE를 이용해서 위상동기루프(PLL) Micromodeling으로 설계하여 시뮬레이션 하였다. PLL 회로는 위상검출기와 전압제어 발진기 그리고 루프 필터로 이루어져 있다. RC 저역통과 필터와 Butterworth 필터 그리고 Chebyshev 필터 등을 이용하여 입력주파수 변화에 따른 루프필터의 주파수 특성을 분석하였다. 그리고 전압제어 발진기의 자주발진주파수를 2.5kHz, 19kHz로 고정할 때의 주파수 스펙트럼을 분석하였다. 자주발진주파수 2.5kHz에서 Chebyshev 필터의 경우 upper lock range와 lower lock range는 똑같이 1,056Hz, 1,056Hz였고 upper capture range와 lower capture range는 536Hz, 540Hz였다. 또한 시뮬레이션 과정에서 삼각파를 구형파로 바꾸는 VCO의 슈미트 트리거단에서 수렴문제로 인하여 19KHz 이상에서는 상당히 긴 시뮬레이션 시간을 필요로 하는 단점이 있었다. 그렇지만 낮은 주파수대에서 주파수 특성 분석의 용이함과 정확성 및 복잡한 회로의 간략화에서 매크로모델링의 타당성을 보였다. With today's general simulator, PSPICE, a phase-locked loop(PLL), which consists of a phase detector(PD), a voltage-controlled oscillator(VCO), and a low-pass filter(LPF), is designed and simulated in macromodeling technique. By using a RC LPF, a Butterworth, and a Chebyshev LPF in turn, the frequency characteristics of the outputs according to the variations of the inputs are analyzed respectively. When 2.5KHz and 19KHz are selected as two specified free running frequencies in VCO block, the frequency spectrums of the outputs show that in case of the Chebyshev LPF at 2.5KHz, the upper and lower rock ranges have the same frequency ranges, 1056Hz, and the upper and lower capture ranges are 536Hz and 540Hz respectively. Furthermore, the simulation takes a long time especially above 19KHz, because of the convergence problem at schmitt trigger section, where the triangular wave is changed into the rectangular wave. However, this paper shows some validity that this macromodeling technique is one of the easy and accurate methods in analyzing the frequency characteristics, and useful in simplifying the complicated circuits at low frequency band below 19KHz.

체육 서비스조직의 리더십유형과 직무만족 및 조직유효성 간의 관계

천길영,남궁완,최병학,박효찬,홍승달,정석현 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.6

The purpose of the study was to examine the relationship among style of leadership, job satisfaction, and efficacy of sport service organization. In order to achive this purpose three reaserch questions were established. Participants for this study were 300 of 23-50 overaged public workers. Of participations valid data were 279. They completed a modified inventory of the style of leadership, job satisfaction and efficacy of sport service organization. More details, style of leadership Scale modified by Ahn(2000), job satisfaction by Ahn (2000) and efficacy of sport service organization by Kim(2001) were using after remodifing scale to investigate the purpose of this study. Results were analysed in quantitative approaches. Data were collected through self-administered survey. The most three meaningful results of the study were as follows; First, there was influenced to relationship between style of leadership and job satisfaction. Second, there was influenced to relationship between style of leadership and efficacy of sport service organization. Third, there was influenced to relationship among style of leadership, job satisfaction, and efficacy of sport service organization.

Ku-band 위성방송수신용 고안정 DRO에 관한 연구

鄭天錫 울산대학교 1994 공학연구논문집 Vol.25 No.2

본 연구에서는 Ku-band 위성방송 수신장치를 위하여 유전체 공진기를 이용한 GaAs MESFET 고안정 발진기 DRO를 설계하여 구현하였다. 유전체 공진기와 마이크로스트립 선로 사이의 결합계수 β가 공진기의 Qex 값에 미치는 관계식을 해석적으로 유도하였다. 발진기의 결합감도 ( ?? )를 0.5이하로 유지시키기 위해 유전체 공진기와 기판 사이에 Spacer를 삽입한 발진기를 제작하여 Spacer가 없는 경우와의 반사계수 특성을 비교하였다. 이 발진기의 최대출력은 5dBm이였고, 0∼100℃ 온도변화 범위 내에서 발진주파수의 편차는 10.678 GHz ±100KHz (p-p)이었다. Spacer를 삽입한 결과 발진기의 주파수 온도 안정성이 2배정도 개선되었다. In this study, a highly stable GaAs MESFET oscillator using the dielectic resonator for Ku-band satellite broadcasting systems was designed and implemented. The relationship equation between the coupling coefficient βand the Qex value by couping the dielectric resonator and the microstrip line was obtained analytically. In order to keep the coupling sensitivity ( ?? ) of the oscillator less than 0.5, a spacer was interposed between the dielectric resonator and the substrate, the characteristics of the reflection coefficient of the oscillator with the spacer was compared with those of the oscillator without the spacer. The maximum outut power of the oscillator was 5 dBm, and the frequency drift, which shows the frequency temperature stability, was 10.678GHz ±100KHz (p-p) within the range of the temperature variation of 0∼100℃. The frequency temperature stability of the oscillator was doubled as a result of the interposition of the spacer.

Ku-Band 위상고정 루프 발진기에 관한 연구

鄭天錫 울산대학교 1995 공학연구논문집 Vol.26 No.1

본 연구에서는 VCDRO를 사용한 고안정 저잡음 Ku-Band PLL 발진기를 설계하였다. 크리스탈 발진기를 사용함으로써 얻어지는 안정된 약 83MHz의 기준 주파수를 합성하기 위하여 PLL회로의 설계과정 및 동작특성을 제어이론을 바탕으로 해석하였다. Ku-Band PLL 발진기의 위상잡음은 위상고정 귀환루프의 안정화로 30dB이상 개선되었다. In this paper, a highly stable low noise Ku-Band PLL Oscillator using the VCDRO(Voltage Controlled Dielectric Resonator Oscillator) was designed. Design procedure and operation characteristics of PLL circuit were analyzed on the basis of control theory to synthesize the reference frequency about 83MHz frequency which should be stable by using crystal oscillator. The Phase noise of the Ku-band PLL VCDRO was improved 30dB by the stabilization of the PLL feed back loop.

소형 능동 파라보릭 UHF 수신 안테나에 관한 연구

정천석 울산대학교 1995 공학연구논문집 Vol.26 No.2

소형 능동 파라보릭 UHF 수신 안테나를 설계하여 그 특성을 시험하였다. 텔레비젼 수신용 안테나로 가장 널리 사용되고 있는 Yagi 안테나는 구조가 간단하고 지향성 및 이득특성이 좋으나 방사 주파수에 대한 반파장 길이의 소자를 여러개 사용해야 하므로 치수가 커지고 주파수 대역이 좁아, 설치 취급등에 불편을 느낄 경우가 많다. 본 연구에서는 설치가 용이하게 소형이면서 화질이 좋은, 1파장의 배트윙형 루프안테나를 대칭으로 배열, 동상 결합한 복사기와 파라볼라 반사기로써 UHF 채널에서 비교적 양호한 단일지향성을 얻고 있다. 본 안테나는 능동소자를 이용한 저잡음 광대역 증폭기를 삽입함으로써 다소자 Yagi 안테나에 비준될 전후방비를 갖는 외에, 그 이득도 최고 30dB까지되어 일반 수상 안테나로 뿐만 아니라, 고우스트 방지용 실내 안테나로써도 사용이 가능하다. A small active parabolic UHF receiving antenna is designed and tested. The Yagi antenna, which is most widely used for television receiving, has simple form, good directivity as well as high gain, but it must be made with several linear elements of half wave length. Therefore, the dimension of multi-element Yagi antenna becomes bulky and so often it is inconvenient to install and handle because of its big size. Moreover the frequency bandwidth of the Yagi antenna is not broad enough to UHF TV channels. A small active parabolic UHF receiving antenna designed in this study is not only small enough to install easily but also assures good quality of picture. It is composed of a parabolic reflector and a radiator. The radiator with shape of batwing in one wavelength of loop antenna is fixed symmetrically and couple in phase. This antenna has shown a relatively good unidirectivity as well as the good F/B(front to back) ratio comparable to those of multi-elements Yagi antenna. The total gain of the antenna can be increased to maximum 30dB by adding to a low noise wide band amplifier. AS a result, this antenna can be used as a UHF TV receving and may become better antighost antenna.

Laplace 變煥을 利用한 Propped Cantilever Beam의 처짐解析에 關한 硏究

鄭海駿,尹錫天 충남대학교 공업교육연구소 1978 論文集 Vol.1 No.1

As the methods of calculating deflection of structures, various ordinary differential equations, that is, the Unit load method, the Moment area method, and Castigliano's theorm have been used. But here the anothers applied Laplace tranform to in the deflection analyses of the propped cantilever beams. The result shows the deflections calculated by Laplace transform are the same values those from ordinary solutions, and are better than the others in efficiency.

연근 분말 첨가가 식빵 반죽에 미치는 영향

김영숙,전순실,정승태,김래영 한국조리과학회 2002 한국식품조리과학회지 Vol.18 No.6

The quality characteristics of dough with lotus root powder were investigated. As the content of lotus root powder increased, doughs showed higher water absorption, lower stability and longer development time than control as measured with a farinograph. Extensibility decreased with the increase of lotus root powder. As the addition of lotus root powder increased, the doughs has higher gelatinization temperatures and maximum viscosities than control as measured by amylograph. And the pH of the dough also increased by the increase of lotus root powder.

都市主婦의 結婚 適應度에 關한 硏究

金惠貞,李蓮淑,任春淑,鄭明姬,曺鏞旬,黃智暎 효성여자대학교 가정대학 학도호국단 1984 家政大論集 Vol.3 No.-

We measured general marital adjustment of the housewives who ilve in Daegu. We analysed marital affectional expression, cohesion, consensus and satisfaction and also analysed marital adjustment according to the level of education or length or marriage. The results are as follows; 1. The level of general marital adjustment of the urban housewives was medium. 2. According to factor analysis, the level of marital affectional expression was medium, the level of marital satisfaction and consensus was high, and the level of cohesion was low. 3. The more educated, the higher the degree of marital adjustment in general. 4. The marital adjustment was lowest in housewives whose length of marriage was 9-11 years. The second lowest were 3-5 years and 21-23 years. The highest was 15-17 years.

비행청소년의 식생활태도와 식이자기효능감에 관한 연구

이정숙,이현자,송병춘,김은경,이춘복,김석환 대한지역사회영양학회 2008 대한지역사회영양학회지 Vol.13 No.5

The purpose of this study was to identify the factors associated with dietary attitudes and dietary self-efficacy of juvenile delinquents. Out of 110 questionnaires distributed to the juvenile detention home students in Daegu, and 150 questionnaires distributed to the juvenile detention home students in Anyang, 210 were analyzed (80.7% analysis rate). These data were analyzed by SPSS program. The results are summarized as follows. Almost all parents’ educational levels showed ‘graduation of middle school’, and only 43.8% of the juvenile detention students were living with parents. In case of incoming status, average income per month was 2,000,000 won, which was lower than normal one. Diet attitude score was higher in boy students than girl students (p < 0.05). There was a higher score of diet attitude in higher educational levels of father. The average score of dietary self-efficacy was 2.51 ± 0.86. This value was lower than the normal juvenile. There was a higher diet attitude score in the higher dietary self-efficacy score (p < 0.001). Therefore, proper nutrition education is required to improve their dietary self-efficacy. The results of this study could be useful data to plan and develop nutritional education programs of juvenile delinquents.

Asphalt로 피복된 Portland Cement를 使用한 Concrete의 諸性質

尹錫天,李昌甲,洪元杓,鄭秀永,南宰鉉 충남대학교 공업교육연구소 1982 論文集 Vol.5 No.1

The construction works with concrete has the potential problems of water tightness. The conventional treatments for water-tight concrete are not satisfactory in terms of strength and water tightness. This study was to investigate the effects and application of the asphalt-coated portland cement on water-proof of the concrete and its influences on the physical properties of the concrete. The asphalt-coated portland cement, which is hereafter referred to as ACPC, was made by coating ordinary portland cement with asphalt in the rate of weight ranging from 0.5 to 1.0 percent. In this process, Calcium Chloride and Sodium Silicate were tried as the hardening time accelerator for producing ACPC, and carbon black, talc and other materials were tested for their effectiveness as pore filler. The specimens were prepared and tested with the various amounts of additives as a variable factor to find the optimum material. The analysis was mainly focused at water tightness, physical properties of the concrete and working conditions. The major findings of this experiment are as follows ; 1) Water-proof Test ① The specimens of ACPC and ordinary portland cement(OPC) were tested under the pressures of 3 and 9 kilograms per square centimeter per 24hours respectively and compared. The OPC specimens showed considerable amount of leakaged water while the ACPC specimens were rated lower permeabilities of 89%/28days, 40%/56days and21%/84days under the abovementioned pressure conditions. The most successful composition for water-proof was identified as ACPC added with Calcium Chloride and carbon black. ② The ACPC demonstrated its superiority in absorption test. The absorption amount of OPC for l hour was greater than that of ACPC for 24hours. 2) Compressive Strength Test Four kinds of specimens of ACPC aging 7, 28, 56 and 84days were tested and compared for their respective results of OPC. The ACPC added with carbon black was lower than OPC in compressive strength in the case of curing ages of 7 and 28days but ACPC was superior to the OPC in the specimens aging 56 and 84days. The ACPC added with others except carbon black exposed their lower compressive strength in all circumstances compared with the OPC specimens. 3) Slump Test The slump of ACPC with various additives such as carbon black, talc or clay was 21.6 centimeter which was higher than the OPC of 18.4centimeter slump. This result concluded that ACPC was much favorable in workability in comparison with that of the OPC. The conclusions are summarized as follows; 1) The optimum mixture for water tightness and compressive strength of concrete was found at 0.5% of SACPC, Calcium Chloride and carbon black respectively at the rate of the weight of cement.