THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE Sep.; 26(9),

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1 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE Sep.; 26(9), ISSN (Print) ISSN X (Online) The Implementation of the Compensation Algorithm of Time Delay for Microwave Polar Transmitters 김민수 이건준 이영철 Min-Soo Kim Kun-Joon Lee Young-Chul Rhee* 요약,.,., 9.3 GHz 97 nsec, 12 MHz,,, 3.7 MHz. Abstract In this paper, We made the microwave polar transmitter based on the software to analyze the synchronization status between the phase signal and the amplitude signal of polar transmitter, and analyzed the result. In order to solve the time delay mismatch problem, we applied simplified compensation algorithm and compared the synchronization status between the two paths before and after compensation. Before compensation, the value of time delay mismatch was the maximum of 97 nsec at 9.3 GHz with the occupied bandwidth of 12 MHz, but after applying the compensation algorithm, the signals between the two paths were synchronized, and we identified the occupied bandwidth could recover to the previous 3.7 MHz. Key words: Polar Transmitter, Compensation Algorithm, Time Delay, Mismatch, Synchronization, Phase, Amplitude. 서론,, - / - (Multi-Mode/Multi-Band) RF. [1],[2].,., SDR (SW ) (No ). ( ) (LICT Co., Ltd.) * (Department of Information & Communication Engineering, Kyungnam University) Manuscript received July 3, 2015 ; Revised September 11, 2015 ; Accepted September 14, (ID No S) Corresponding Author: Min-Soo Kim ( mskim@lict.co.kr) 790 c Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved.

2 (Software Defined Radio) (reconfiguration) [3].,,, [4] [7].,, [8],[9].,,.,. [10],[11].,., -,. 1. QPSK, QPSK I/Q. DDS (PM), 그림 1. Fig. 1. The block diagram of the designed polar transmitter.. (AM) PM AM. PM AM -.. 경로동기화를위한보정알고리즘구현 - 2 [10],[11]. (AM), (PM),,,., PM, AM ,,. 3 (1) (2). cos (1) 791

3 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 26, no. 9, Sep (Steepest Descent) [12]. (5) 그림 2. Fig. 2. The configuration for compensating a mismatch due to the time-delay between the two signal paths., (adaptation step size). (5) (6). (6) (6) (statistical expectation gradient) (stochastic gradient) (instantaneous gradient) (7). (7), (8). 그림 3. Fig. 3. The configuration of compensation blocks for synchronization between the two signal paths. cos (2) (1) (2) (3). cos (3) MSE(Mean Square Error) (cost function) [10] (4). cos (4) (Statistical Expectation Oper- ator) [10].,.., cos cos cos, (9). cos (9) PM AM (8) (9) 792

4 그림 4. Fig. 4. The simulation environment to apply the active filter for mismatch compensation.. 4., (variable time delay). 5.. 그림 5. Fig. 5. The simulation result of the system with active filter. 그림 6. - Fig. 6. The configuration of feed-back loop for synchronization between the two signal paths. 6 FPGA. - ADC MHz IF. DDS 20 MHz - I/Q, CO- RDIC. AM/PM TIME TRACK (time delay) ADC 14 bit FPGA -. ADC 14 bit, -. - offset 8 bit FPGA DDS DDS Skew 793

5 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 26, no. 9, Sep 표 1. Table 1. The packet structure for data communication. Preamble(0 AA) Skew(0 66) Size Data 20 byte 3 byte 1 byte 256 byte 3-Byte. Preamble 0 AA.. Skew , Preamble Skew Sampling point(phase) start. Size Rx, AP. AP FPGA(Tx) ( ). Data 256 byte, Rx Size.,. 6. PME(Peak Magnitude Event) [13]. 7. -,,,.,. FPGA 그림 7. 6 AM/PM TIME TRACK Fig. 7. The flow chart for the mismatch compensation in AM/PM TIME TRACK block in Fig. 6. 그림 8. Fig. 8. The relationship between radius and phase variation..,.,... 폴라송신기의위상과진폭신호동기화분석,. 794

6 마이크로파 폴라 송신기의 시간지연 보상 알고리즘 구현 그림 9. 진폭과 위상이 비동기되었을 때의 진폭과 위상변 화의 관계 Fig. 9. The relationship between radius and phase variation. 하고 피드-백 되어 돌아오는 신호를 확인한 다음, 보정알 고리즘을 적용 전과 적용 후를 분석하였다. AM 신호와 PM 신호 출력의 동기화 분석을 위해 폴라 송신기의 출력에서 재 결합시켜 피드-백된 신호를 보정 알고리즘을 적용하여 검증하였다. 비교 검증을 위하여 송 신데이터를 내부 DDS을 사용하여 20 MHz 변조하여 비 교를 위한 기준 신호를 만들어 DAC을 통하여 출력하게 하고, 또 다른 송신 데이터를 외부 DDS와 상향변환기를 거쳐 피드-백되어 복조된 20 MHz 신호와 비교하였다. 보정알고리즘을 적용하기 전 그림 10과 같이 기준 송 그림 10. 두 경로 간의 지연 부정합 차이로 인한 결과. (a) 송신신호, (b) 피드-백 신호 Fig. 10. The result of the delay mismatch between the two signal paths due to the difference. (a) Transmitted signals, (b) feed-back signals. 그림 11. 보정알고리즘을 적용한 후 결과. (a) 송신신호, (b) 피드-백 신호 Fig. 11. The result after applying the proposed compensation algorithm. (a) Transmitted signals, (b) feed-back signals. 신 신호(a) 대비 피드-백 되어 복조된 신호(b)는 그림 9에 서 설명한 것과 같이 두 경로 간의 비동기로 인한 지연 부정합이 발생을 하여 진폭의 최소 변화 구간이 아닌 지 점에서 위상의 변화가 일어나고 있음을 볼 수 있다. 그림 7과 그림 8에 의해 보정알고리즘을 적용시킨 후, 그림 11과 같이 진폭의 최소 변화 구간에서 위상변화가 일어나며, 피드-백 신호는 송신 기준 신호와 일치하는 것 그림 12. 스펙트럼 결과비교. 보상알고리즘 적용 전(a)과 적용 후(b) Fig. 12. The result of spectrum comparison. Without compensation algorithm(a), with compensation algorithm (b). 795

7 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 26, no. 9, Sep 표 2. Table 2. The occupied bandwidth due to differences of the delay mismatch. Time delay difference(nsec) Occupied bandwidth(mhz) X- 12., 12(a), AM PM 58 nsec, 12(b),. 12,. 2.. 결론. -,.,,,, 58 nsec.,. 9.3 GHz, 97 nsec, 12 MHz.,, 3.7 MHz. -,.. References [1] T. D. Stezler, I. G. Post, J. H. Havens, and M. Koyama, "A V single chip GSM transceiver RF integrated circuit", IEEE Journal of Solid-State Circuits, vol. 30, no. 12, pp , Dec [2] Kyoohyun Lim, Sunki Min, Sanghoon Lee, Jaewoo Park, Kisub Kang, Hwahyeong Shin, Hyunchul Shim, Sechang Oh, Sungho Kim, Jongryul Lee, Changsik Yoo, and Kukjin Chun, "A 2 2 MIMO tri-band dual-mode directconversion CMOS transceiver for Wor ldwide WiMAX/ WLAN applications", IEEE Journal of Solid-State Circuits, vol. 46, no. 7, pp , Jul [3] F. H. Raab, P. Asbeck, S. Cripps, P. B. Kenington, Z. B. Popovic, N. Pothecary, J. F. Sevic, and N. O. Sokal, "Power amplifiers and transmitters for RF and microwave", IEEE Transactions on Microwave Theory and Techniques, vol. 50, no. 3, pp , Mar [4] W. C. Yao, N. K. Chien, "Tuneable delay compensation circuit in polar loop transmitter for WiMAX applications", 2010 APMC, pp , Dec [5] Jae Woong Jeong, S. Ozev, S. Sen, and T. M. Mak, "Mea surement of envelope/phase path delay skew and envelop path bandwidth in polar transmitters", IEEE 31st VLSI Test Symposium 2013, pp. 1-6, May [6] G. Huebe, R. Staszewski, Precise Delay Alignment bet- 796

8 ween Amplitude and Phase/Frequecy Modulation Paths in a Digital Polar Transmitter, First Edition, Wiley IEEE Press, pp , [7], " ",, 14(5), pp , [8] D. Nestor Lopez, Xufeng Jiang, and D. Maksimovic, Z. Pop vic, "Class-E power amplifier in a polar EDGE transmitter", IEEE MTT-S IMS 2006, pp , Jun [9] Xufeng Jiang, N. D. Lopez, and D. Maksimovic, "A switched mode envelop tracker for polar EDGE transmitter", IEEE 37th Power Electronics Specialists Conference 2006, pp. 1-7, Jun [10] J. -F. Bercher, C. Berland, "Adaptive delays alignment in polar transmitter architecture", IEEE Transaction on Circuits and Systems, pp. 1-9, [11] Feipeng Wang, "Design of wide-bandwidth enve lopetracking power amplifiers for OFDM applications", IE- EE Transaction on Microwave Theory and Techniques, vol. 53, no. 4, pp , Apr [12] K. T. Vagner, M. I. Doroslovacki, "Proprotionate-type seepest descent and NLMS algorithms", 41st Annual Conference on Informations Sciences and Systems, pp , Mar [13] Saleh Osman, Earl W. McCllne, JR, United States Patent Patent No.2 US 8,126,409 B : ( ) : ( ) : ( ) : ( ) [ 주관심분야 ], 1981 : [ 주관심분야 ], : ( ) : ( ) : ( ) 2013 : ( ) [ 주관심분야 ],, 797