• Title/Summary/Keyword: DDC(Digital Down Converter)

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Linkage between Digital Down Converter System and Spectrum Sensing Method (Digital Down Converter 시스템과 스펙트럼 센싱 기법 연동 방안)

  • Hong, Moo-Hyun;Moon, Ki-Tak;Kim, Ju-Seok;Kim, Kyung-Seok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.3
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    • pp.43-50
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    • 2010
  • DDC(Digital Down Converter) is a conversion technology to decimate to a lower sampling rate and DDC for the future development of communications technology has the necessary skills. So, it has been recognized in the wireless and the SDR(Software Defined Radio) system as essential components. In addition, research is underway on spectrum sensing for efficient communications environment due to the shortage of frequency resources. In this paper, the DDC systems were analyzed for CIC(Cascaded Integrator Comb) Filter, WDF(Wave Digital Filter), SRC(Sample Rate Conversion) each module. Moreover, we proposed a linkage effectively between DDC system and Spectrum Sensing for improve the efficiency of use of frequency by computer simulations. The simulation results of the DDC system was applied to the spectrum sensing capabilities. Also, performance and complexity of the results were derived and proposed system was the result of the check.

The Implementation of DDC for the WLAN Receiver (WLAN 수신기를 위한 Digital Down Converter (DDC) 구현)

  • Jeong, Kil-Hyun
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.2
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    • pp.113-118
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    • 2012
  • In this paper, we discuss the design of the Digital Down Converters for the IEEE 802.11 wireless LAN receiver, which can be used for the customized receiver. The customized receiver can be used for special puropsed services which cannot be realized using the general custom chip. In the OFDM receiver, DDC receives the up sampled Inphase/Quadrature signal from the AD converter and process down sampling and filtering procedures using the Cascaded Intergrator Filter and FIR filters. We discuss the structure and design methodology of DDC's and analyze the simulation results.

Design of DUC/DDC for the Underwater Basestation Based on Underwater Acoustic Communication (수중기지국 수중 음향 통신을 위한 DUC/DDC 설계)

  • Kim, Sunhee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.5
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    • pp.336-342
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    • 2017
  • Recently, there has been an increasing need for underwater communication systems to monitor ocean environments and prevent marine disasters, as well as to secure ocean resources. Most underwater communication systems adopted acoustic communication with a consideration of attenuation, absorption, and scattering in conductive sea water, and developed fully digital modems based on processors. In this study, a digital up converter (DUC) and a digital down converter (DDC) was developed for an underwater basestation based on underwater acoustic communication systems. Because one of the most important issues in underwater acoustic communication systems is low power consumption due to environmental problems, this study developed a specific hardware module for DUC and DDC. It supported four links of underwater acoustic communication systems and converted the sampling rate and frequency. The systemwas designed and verified using Verilog-HDL in ModelSim environment with the test data generated from baseband layer parts for an underwater base station.

Digital Down Converter System improving the computational complexity (복잡도를 개선한 Digital Down Converter 시스템)

  • Moon, Ki-Tak;Hong, Moo-Hyun;Lee, Joung-Seok;Kim, Kyung-Seok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.3
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    • pp.11-17
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    • 2010
  • Multi-standard, multi-band, multi-service system to ensure a flexible interface between the SDR (Software Defined Radio) technology for the implementation of the Stability and Low-Power, Low-Calcualrion DDC (Digital Down Conversion) technology is essential. DDC technology consists of a digital channel filter. This is a typical digital filter because of the limited fisheries are vulnerable to overflow and rounding errors are drawbacks. In this paper, we overcome this disadvantage, we propose the structure of the DDC. The way WDF (Wave Digital Filter) Structural rounding error due to the structural resistance to noise. Therefore, This is the useful structure when the filter coefficients's word length is short. In addition, since IIR filters based on FIR filters based on the amount of computation is reduced because fewer than filter's tap. The proposed structure is used in DDC that CIC (Cascaded Integrator Comb) filter, WDF, IFOP (Interpolated Fourth-Order Polynomials) were analyzed with respect to, the results were confirmed by computer simulation.

Design of Digital Transmitter and Receiver Modules in ILS (항공 계기착륙 디지털 송수신 모듈 설계)

  • Choi, Jong-Ho
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.4 no.4
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    • pp.264-271
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    • 2011
  • ILS(Instrument Landing System) is the international standard system for approach and landing guidance. ILS was adopted by ICAO(International Civil Aviation Organization) in 1947 and is currently being used in commercial systems. To design the digital transmitter and receiver modules that can be mounted in the integrated ILS, we propose the digital design methods of digital double AM modulator and demodulator using FPGA chip, DDS(Direct Digital Synthesizer) for generation of sampling clock, demodulator of DDC(Digital Down Converter) structure, and spectrum analyzer using DSP chip. We demonstrate the efficiency of the proposed design method through experiments using developed transmitter and receiver modules. This system can be used as a high-performance commercial system.

A Low-power Digital Down Converter Architecture Using Interpolated IIR Filters (Interpolated IIR 필터를 사용한 저전력 디지털 다운 컨버터 아키텍처)

  • 장영범
    • Proceedings of the IEEK Conference
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    • 2000.11d
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    • pp.127-130
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    • 2000
  • This paper proposes a low-Power DDC(Digital Down Converters) architecture for IF(Intermediate frequency) signal processing. It is shown that concept of conventional interpolated FIR filters can be expanded to IIR filters for DDC applications. Also in the paper, power dissipations for the proposed architecture and conventional ones are estimated.

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Optimal equivalent-time sampling for periodic complex signals with digital down-conversion

  • Kyung-Won Kim;Heon-Kook Kwon;Myung-Don Kim
    • ETRI Journal
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    • v.46 no.2
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    • pp.238-249
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    • 2024
  • Equivalent-time sampling can improve measurement or sensing systems because it enables a broader frequency band and higher delay resolution for periodic signals with lower sampling rates than a Nyquist receiver. Meanwhile, a digital down-conversion (DDC) technique can be implemented using a straightforward radio frequency (RF) circuit. It avoids timing skew and in-phase/quadrature gain imbalance instead of requiring a high-speed analog-to-digital converter to sample an intermediate frequency (IF) signal. Therefore, when equivalent-time sampling and DDC techniques are combined, a significant synergy can be achieved. This study provides a parameter design methodology for optimal equivalent-time sampling using DDC.

A Low-power Decimation Filter Structure Using Interpolated IIR Filters (Interpolated IIR 필터를 이용한 저전력의 데시메이션 필터 구조)

  • 장영범;양세정
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.8B
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    • pp.1092-1099
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    • 2001
  • 본 논문에서는 무선 통신 시스템의 중간주파수 처리 단을 디지털로 신호 처리하는 DDC(Digital Down Converter)의 저전력 아키텍처를 제안한다. FIR 필터의 계산량을 줄이기 위해서 개발된 Interpolated FIR 필터가 DDC의 데시메이션 필터로 널리 사용되고 있다. 본 논문은 이와 같은 Interpolated FIR 필터의 개념이 IIR 필터에도 적용될 수 있음을 보이고, 전력 소모와 구현 면적이 기존의 Interpolated FIR 구조보다 더욱 감소된 Interpolated IIR 필터 구조를 제안하였다. CDMA IS-95 DDC 사양의 데시메이션 필터를 FIR 구조, Interpolated FIR 구조, IIR 구조, Interpolated IIR 구조로 구현하여 이 4가지 구조들의 전력소모와 구현 면적을 비교하였으며 제안된 Interpolated IIR 구조가 기존의 Interpolated FIR 구조에 비하여 15.2%의 소모전력 감소와 35.3%의 구현면적의 감소를 달성할 수 있음을 보인다.

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Noise Automatic Gain Control to Stabilize Radar Performance (레이다 성능 안정화를 위한 잡음 AGC)

  • Kim, Kwan-Sung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.10 no.4
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    • pp.132-137
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    • 2007
  • The dynamic range of the radar which uses digital signal processors is limited by ADC(Analog-to-Digital Converter). That parameter and ADC loss depend on the noise level of radar receiver. In order to stabilize the performance of radar systems, it is necessary to maintain the noise level constantly. This paper presents the noise AGC(Automatic Gain Control) concept that can keep the noise level constantly and proves that the concept is acceptable through the hardware test and evaluation.

Performance Comparison of Channelization Schemes for Flexible Satellite Transponder with Digital Filter Banks (디지털 필터뱅크 기반 플렉서블 위성중계기를 위한 채널화 기법의 성능비교 연구)

  • Lee, Dong-Hun;Kim, Ki-Seon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.3
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    • pp.405-412
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    • 2010
  • The purpose of this paper is to compare complexity and to assess flexibility of competing transponder architectures for satellite communication services. For performance comparison, we consider three channelization techniques: digital down converter(DDC) based on the use of the cascaded integrator-comb(CIC) filter, tuneable pipeline frequency transform(T-PFT) based on the tree-structure(TS) and variable oversampled complex-modulated filter banks(OCM-FB) based on the polyphase FFT(P-FFT). The comparison begins by presenting a basic architecture of each channelization method and includes analytical expressions of the number of multiplications as a computational complexity perspective. The analytical results show that DDC with CIC filter requires the heavy computational burden and the perfect flexibility. T-PFT based on the TS provides the almost perfect flexibility with the low complexity over DDC with the CIC filter for a large number of sub-channels. OCM-FB based on the P-FFT shows the high flexibility and the best computational complexity performance compared with other approaches.