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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Broadcast Engineering
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Journal DOI :
The Korean Institute of Broadcast and Media Engineers
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Volume & Issues
Volume 8, Issue 4 - Dec 2003
Volume 8, Issue 3 - Sep 2003
Volume 8, Issue 2 - Jun 2003
Volume 8, Issue 1 - Mar 2003
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Study on the technology of ATSC terrestrial DTV broadcasting service using single frequency networks
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 109~115
In this paper we propose an efficient method to broadcast digital television signals using Single Frequency Networks (SFNs) in the Advanced Television Systems Committee (ATSC) transmission systems. Since the proposed schemes to synchronize multiple transmitters minimize the changes from the conventional ATSC system, the hardware complexity for the changes is very low. Our simulation results show that the proposed scheme makes less than 0.1 dB degradation at the threshold of visibility (TOV： BER= 3
) in the additive white Gaussian noise (AWGN) channel. It is possible to reduce the performance degradation by increasing an initialization period of the proposed scheme.
Development of Interference Cancellation DSP Module and Software for DTV-OCR
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 116~125
In this paper, we introduce a newly developed DSP module and Software which Is applicable to DTV-OCR and is designed to cancel the interference signal. In general, RF repeater has problems of system oscillation and signal Quality degradation due to feedback interference signal coming from transmit antenna. In this paper, we demonstrate newly developed DSP HW and SW module for cancelling the interference signal by investigating the field data measured through a RF repeater. Also, the structure and signal processing method for non-regenerative repeater system based on the newly developed DSP HW and SW module is illustrated as well.
Development of a DTV RF Capture and Regeneration System
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 126~135
To investigate the DTV coverage especially in downtown areas and improve the performance of DTV receivers, it is necessary to capture the receiving DTV signals that contain the complex characteristics of the real-world RF environments and regenerate them in a laboratory without the performance degradation. In this paper, we developed a DTV RF capture and regeneration system adapting digital signal processing and high speed hard disk storage techniques and analyze its characteristics. The system can capture and replay the DTV RF signals based on a real-time condition in a hard disk. There Is no time limit for capturing RF data within the installed storage capacity. We can expect various Possible applications for this system such as a tool for the development of the receiver performance analysis, design and analysis for the DTV coverage areas, etc.
DOA estimation based beamforming technique for DTV reception performance enhancement
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 136~145
This paper proposes a DTV receiver using beamforming techniques to improve indoor and mobile reception. The proposed DTV receiver estimates the directions of arrival (DOAs) of incoming signals using Capon's DOA estimation method and generates an adaptive antenna beam pattern to the estimated DOA of the mainpath signal to Improve the channel condition. After beamforming, a following decision feedback equalizer (DFE) removes the remaining multipath components. The proposed receiver can be implemented with a conventional DTV receiver without anymodification. The performance of the proposed receiver is analyzed with modified Brazilian field test models, which include DOA information of Incoming signals. Simulation results show that the proposed receiver can satisfy the threshold of visibility (TOV) when input signal to noise ratio is slightly over 10 dB.
Timing-offset compensation techniques in ATSC DTV receivers
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 146~152
ATSC DTV receivers use repetitive data segment syncs or Gardner algorithm as a tuning recovery circuit. Many multipath signals can induce timing-offset in the symbol timing recovery circuit using Gardner algorithm and this timing-offset shifts sampling instant to the wrong points, causing the performance of the equalizer to become nr. When many echoes exist, the optimal sampling instant will be the Point at which the main-path has a peak value. In this paper, by using channel correlation techniques, we find the optimal sampling instant, thereby compensating the timing offset and improving DTV reception performance. We analyzed the Performance enhancement of DTV receivers using the timing offset compensator.
A Design of Adaptive Equalizer for Terrestrial Digital Television Receivers
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 153~162
This paper describes a structure of adaptive equalizer to improve reception performance of ATSC digital television (DTV) for 8-VSB receivers. There are many strong and dynamic echoes affecting reliable reception of DTV signal. Conventional DFE based least mean square (LMS) algorithm is readily implemented and has good Performance. There are still problems to be solved, however, in handling strong echoes and indoor reception. In this paper, structure of adaptive equalizer to mitigate these Problems in strong multipath interference conditions and indoor reception environment is first presented. Methods to reduce error propagation effects on DFE and initialization scheme of filter coefficients for fast convergence are then introduced. Computer simulation results prove that an adaptive equalizer with proposed design methods can combat with Brazil Ensemble and the Threshold of Visibility(TOV) is improved.
A Study on Joint Source/Channel Coding for MPEG-4 Video Transmission
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 163~171
In this paper, we develop an approach toward Joint Source-Channel Coding for MPEG-4(Moving picture Experts Group) based video coding In fixed and mobile reception environment. We have considered channel environment of AWGN and mobile reception. The source coder used MPEG-4 video. the channel coder used RCPC(Rate Compatible Punctured Convolution) and the modulation method used QPSK(Quadrature Phase Shift Keying) modulation. This study determined optimum Trade-off point between source bit rate and channel coding rate In variable channel states. We compared Joint Source/channel Coding method and general constant bit rate transmission. In this results, Joint Source/channel Coding was appeared better performance than constant bit rate transmission.
Extracting & Tracking Algorithm for Facial Motion Capture Animation
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 172~180
In this paper, we propose fast and precise extracting & tracking algorithm based on general camera and frame grabber for facial motion capture animation. Proposed algorithm consists of two steps. extracting and tracking. The former is to separate multiple markers from input image using region merging based on neural networks. The latter Is to track extracted multiple markers at each frame using tracking algorithm based on neural networks. In the experiment, we could remove noise and reduce processing time in the step of extraction. In addition, we could have good tracking results in the low frame rates.
A Study on New Hierarchical Motion Compensation Pyramid Coding
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 181~197
Notion Compensation(MC) technique using Sub-Band Coding with the hierarchical structure is efficient to estimate real motion. In the hierarchical pyramid method, low-band MC pyramid method is popular, where the upper layer estimate the glover motion and next lower layer estimate the local motion. The low-band MC pyramid scheme has two problems. First, because the quantization errors at lower layer are accumulated when using coding and quantizing, it is impossible to search the exact Motion Vector(MV) Second, because of the top-down search problem in the hierarchical structure, MV mismatch in upper layer causes serious MV in lower layer So. we propose new hierarchical MC pyramid method based on edge classification. In this Paper, we show that the performance of proposed Pass-band motion compensation pyramid technique is better than low-band motion compensation pyramid. Also, in the pyramid motion estimation, we propose initial MV estimation scheme based on the edge-pattern classification. As a result, we find that PSNR was increased.
A Speech Recognition System based on a New Endpoint Estimation Method jointly using Audio/Video Informations
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 198~203
We develop the method of estimating the endpoints of speech by jointly using the lip motion (visual speech) and speech being included in multimedia data and then propose a new speech recognition system (SRS) based on that method. The endpoints of noisy speech are estimated as follows : For each test word, two kinds of endpoints are detected from visual speech and clean speech, respectively Their difference is made and then added to the endpoints of visual speech to estimate those for noisy speech. This estimation method for endpoints (i.e. speech interval) is applied to form a new SRS. The SRS differs from the convention alone in that each word model in the recognizer is provided an interval of speech not Identical but estimated respectively for the corresponding word. Simulation results show that the proposed method enables the endpoints to be accurately estimated regardless of the amount of noise and consequently achieves 8 o/o improvement in recognition rate.
Spatial Frequency Adaptive Image Restoration Using Wavelet Transform
Journal of Broadcast Engineering, volume 8, issue 2, 2003, Pages 204~208
In this paper, a new matrix vector formulation for a wavelet-based subband decomposition is introduced. This formulation provides a means to compute a regular multi-resolution analysis over many levels of decomposition. With this approach. any single channel linear space-invariant filtering problem can be cast into a multi-channel framework. This decomposition Is applied to the linear space-invariant image restoration problem and propose a frequency-adaptive constrained least squares(CLS) filter. In the proposed filter, we use different parameters adaptively according to subband characteristics. Experimental results are presented for the proposed frequency-adaptive CLS filter These experiments show that if accurate estimates of the subband characteristics are available, the proposed frequency adaptive CLS filter provides significant improvements over the traditional single channel filter.