• Title/Summary/Keyword: DDS(Direct Digital Synthesizer)

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A Development of DDS Based Chirp Signal Generator and X-Band Transmitter-Receiver for Small SAR Sensor (DDS 기반의 소형 SAR 시스템 송수신장비 개발)

  • Song, Kyoung-Min;Lee, Ki-Woong;Lee, Chang-Hyun;Lee, Woo-Kyung;Lee, Myeong-Jin
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.3
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    • pp.326-329
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    • 2016
  • UAVs(Unmanned Aerial Vehicle) can be used in variant fields fornot only combat, but also recon, observation and exploration. Moreover, UAVs capacity can be expanded to impossible missions for existing surveillance system such as SAR(Synthetic Aperture Radar) technology that collecting images from all weather conditions. In recent days, with development of highly efficient IC and lightened system technology, there are significant increase of researches and demands to make SAR sensor as a payload of UAV. Therefore, this paper contains development process and results of small signal generator and RF device as a core module of SAR system based on the digital device of DDS.

A Single-Chip CMOS Digitally Synthesized 0-35 MHz Agile Function Generator

  • Meenakarn, C.;Thanachayanont, A.
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.1984-1987
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    • 2002
  • This paper describes the design and implementation of a single-chip digitally synthesized 0-35MHz agile function generator. The chip comprises an integrated direct digital synthesizer (DDS) with a 10-bit on- chip digital-to-analog converter (DAC) using an n-well single-poly triple-metal 0.5-$\mu\textrm{m}$ CMOS technology. The main features of the chip include maximum clock frequency of 100 MHz at 3.3-V supply voltage, 32-bit frequency tuning word resolution, 12-bit phase tuning word resolution, and an on-chip 10-bit DAC. The chip provides sinusoidal, ramp, saw-tooth, and random waveforms with phase and frequency modulation, and power-down function. At 100-MHz clock frequency, the chip covers a bandwidth from dc to 35 MHz in 0.0233-Hz frequency steps with 190-ns frequency switching speed. The complete chip occupies 12-mm$^2$die area and dissipates 0.4 W at 100-MHz clock frequency.

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DDS를 이용한 중단파대 국ㆍ영문용 DSC/NBDP 개발에 관한 연구

  • 유형열;김기문
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.3 no.4
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    • pp.805-817
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    • 1999
  • In this paper, the needs for introduction and adoption of MㆍHF DSC/NBDP system and for developments of its circuits and call sequences for use in the maritime mobile services for small-ships, leisure-ships and fishing ships are analyzed, discussed. Also design and implement for MㆍHF(1.6-4MHz) DSC/NBDP system is discussed. Most of casualties have been arisen from small-ships and fishing ships during last 5 years. So, the SAR schematic plans should been prepared to prevent casualties and facilitate the activities of SAR for those ships. DSC/NBDP for MㆍHF system is able to fulfill the roles of efficient SAR communication functions, and to advance the SAR system to small ships and fishing ships. This study is focused on the techniques of processing the DSC call sequences and the ARQ sequences of NBDP system. Especially ARQ sequences are expanded into processing of Korean letters, designed the call sequences and code conversion algorithm for Korean-code. It will be evaluated the availability of Korean-NBDP system. In designing the Transmitting circuits and Receiving circuits, for the carrier generation, DDS(Direct Digital Synthesizer) is used in stead of the Phase Locked Loop and frequency conversion by the mixer, BPF. And PSK modulation signals are directly generated by the controls of DDS, which show the characteristics of Spurious Free Dynamic Range are below -62dBc. Also, the monolithic U subsystem IC which provides various functional components, AD608 is used for designing the receiving circuitsㆍAnd the algorithm of Phasing methode for FSK demodulation are devised to process IF frequency 455kHz in the IF circuits.

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Waveform Generator for W-band Compact Radar (W-band 소형 레이다용 파형발생부)

  • Lee, Man-Hee;An, Se-Hwan;Kim, Young-Gon;Kim, Hong-Rak
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.5
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    • pp.97-102
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    • 2018
  • In this paper, W-band Waveform Generator for compact radar has been designed and fabricated. DDS (Direct Digital Synthesizer) is applied to generate CW (Continuous Wave) and FMCW (Frequency Modulation Continuous Wave) waveform at high speed. We designed two LO (Local Oscillator) paths for functions of distance delay and distance tracking tests at the prpposed system without extra test equipment. Two mode selections are provided by switch. It is observed that fabricated waveform generator performs -91 dBc/Hz phase noise at offset 1 kHz and -63.2 dBc spurious. Proposed W-band Waveform Generator is expected to apply for W-band compact radar transceiver module.

A Multi-Channel Correlative Vector Direction Finding System Using Active Dipole Antenna Array for Mobile Direction Finding Applications

  • Choi, Jun-Ho;Park, Cheol-Sun;Nah, Sun-Phil;Jang, Won
    • Journal of electromagnetic engineering and science
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    • v.7 no.4
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    • pp.161-168
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    • 2007
  • A fast correlative vector direction finding(CVDF) system using active dipole antenna array for mobile direction finding(DF) applications is presented. To develop the CVDF system, the main elements such as active dipole antenna, multi-channel direction finder, and search receiver are designed and analyzed. The active antenna is designed as composite structure to improve the filed strength sensitivity over the wide frequency range, and the multi-channel direction finder and search receiver are designed using DDS-based PLL with settling time of below 35 us to achieve short signal processing time. This system provides the capabilities of the high DF sensitivity over the wide frequency range and allows for high probability of intercept and accurate angle of arrival(AOA) estimation for agile signals. The design and performance analysis according to the external noise and modulation schemes of the CVDF system with five-element circular array are presented in detail.

Phase Noise Analysis of 2.4 GHz PLL using SPD (SPD를 이용한 2.4 GHz PLL의 위상잡음 분석)

  • Chae, Myeoung-ho;Kim, Jee-heung;Park, Beom-jun;Lee, Kyu-song
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.3
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    • pp.379-386
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    • 2016
  • In this paper, phase noise analysis result for 2.4 GHz PLL(phase locked loop) using SPD(sample phase detector) is proposed. It can be used for high performance frequency synthesizer's LO(local oscillator) to extend output frequency range or for LO of offset PLL to reduce a division rate or for clock signal of DDS(direct digital synthesizer). Before manufacturing, theoretical estimation of PLL's phase noise performance should be performed. In order to calculate phase noise of PLL using SPD, Leeson model is used for modeling phase noise of VCO(voltage controlled oscillator) and OCXO(ovened crystal oscillator). After theoretically analyzing phase noise of PLL, optimized loop filter bandwidth was determined. And then, phase noise of designed loop filter was calculated to find suitable OP-Amp. Also, the calculated result of phase noise was compared with the measured one. The measured phase noise of PLL was -130 dBc/Hz @ 10 kHz.

A Study on Design and Performance Evaluation of the Frequency Snthesizer Using the DDS in the Transmitter of the FFH/BFSK System (FFH/BFSK 시스템 송신부에서 DDS를 이용한 주파수합성기 설계 및 성능평가에 관한 연구)

  • 이두석;유형렬;정지원;조형래;김기문
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 1999.11a
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    • pp.161-166
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    • 1999
  • The global trends of mobile communication system is moving toward digitizing, high-speed and large-capacity. Also, to utilize the limited frequency-resource efficiently, spread spectrum system is a mainstream. In this study we are concerning with the fast frequency-hopping system. Instead of the PLL with many problems such as phase-noise, we used the DDS is popular in these days minimizes the disadvantage of PLL. In the case the FFH system is designed using the PLL, it is difficult to be satisfied of the design conditions such as RF badwidth and the settling time of PLL, and it has limitation because of complex circuit by using the balanced modulator. In this study, we evaluated the performance in order to design the FFH system using the DDS. The system that has the improvement of error rate, 1Mhps hopping rate and 5MHz RF bandwidth is designed and evaluated.

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20 MHz-3 GHz Programmable Chirp Spread Spectrum Generator for a Wideband Radio Jamming Application

  • Kim, Sun-Ryoul;Ryu, Hyuk;Ha, Keum-Won;Kim, Jeong-Geun;Baek, Donghyun
    • Journal of Electrical Engineering and Technology
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    • v.9 no.2
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    • pp.771-776
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    • 2014
  • In this paper, an agile programmable chirp spread spectrum generator for wideband frequency-jamming applications from 20 MHz to 3 GHz is proposed. A frequency-mixing architecture using two voltage-controlled oscillators is used to achieve a wideband operating frequency range, and the direct digital synthesizer (DDS)-based chirping method with a two-point modulation technique is employed to provide a programmable and consistent chirp bandwidth. The proposed signal generator provides the various programmable FM signals from 20 MHz to 3 GHz with a modulation bandwidth from 0 to 400 MHz. The prototype successfully demonstrates arbitrary sequential jamming operation with a fast band-to-band hopping time of < 10 ${\mu}sec$.

Design and Implementation of L/Ku-band Broadband Power Detector using Schottky Diode (Schottky 다이오드를 이용한 Six-port용 L/Ku-band 광대역 Power detector 설계 제작)

  • Kim Young-Wan
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2006.05a
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    • pp.615-618
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    • 2006
  • The broadband power detector for direct- onversion Six-port output circuit was designed and implementaed in this paper. The power detector should linearly operated to produce the linear amplitude and phase signal fer input RF signal in required broadband. So, the power detector should be designed under conditions of matching circuit with low VSWR. The designed power detectors, which were implemented in L-band with 50 ohm matching and Ku-band with matching circuit and isolator, respectively, were evaluated in the performances.

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Design of the Transceiver for a Wide-Range FMCW Radar Altimeter Based on an Optical Delay Line (광 지연선 기반의 넓은 고도 범위를 갖는 고정밀 FMCW 전파고도계 송수신기 설계)

  • Choi, Jae-Hyun;Jang, Jong-Hun;Roh, Jin-Eep
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.11
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    • pp.1190-1196
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    • 2014
  • This paper presents the design of a Frequency Modulated Continuous Wave(FMCW) radar altimeter with wide altitude range and low measurement errors. Wide altitude range is achieved by employing the optic delay in the transmitting path to reduce the dynamic range of measuring altitude. Transmitting power and receiver gain are also controlled to have the dynamic range of the received power be reduced. In addition, low measurement errors are obtained by improving the sweep linearity using the Direct Digital Synthesizer(DDS) and minimizing the phase noise employing the reference clock(Ref_CLK) as the offset frequency of the Phase Locked Loop(PLL).