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Broadcasting, IEEE Transactions on

Issue 3 • Date Sep 2000

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Displaying Results 1 - 7 of 7
  • Real-time transcription system for simultaneous subtitling of Japanese broadcast news programs

    Page(s): 189 - 196
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB)  

    There are strong demands to expand captioned broadcasting for TV news programs in Japan. However, keyboard entry of captioned manuscripts for news programs cannot keep pace with the speed of speech because Japanese use ideographic characters. To realize simultaneous subtitling of Japanese news programs, a real-time speech recognition system to handle broadcast news transcription has been developed. Experiments showed that word recognition error rate of the system for studio announcer speech is 2.8% in the real-time recognition and the error rate can reduce to 0.8% by manual correction with an average total delay of 10.4 seconds View full abstract»

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  • Parallel concatenated convolutional coding for an LMDS system with multimedia services

    Page(s): 206 - 214
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (136 KB)  

    The performance of LMDS (local multipoint distribution service) system with parallel concatenated convolutional coding (PCCC) is analyzed and simulated. The channel of a LMDS system is modeled as a Rician fading channel with strong Rician factor because it is generally accepted that there always exists a line-of-sight (LOS) path between base station and subscriber units. The performance is evaluated in terms of codeword error probability. From the simulation results, it is confirmed that the performance is significantly improved by employing the PCCC. The results in the paper can be applied to radio modem design of a LMDS system View full abstract»

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  • A quadrature baseband approach to direct digital FM synthesis

    Page(s): 227 - 230
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (92 KB)  

    The use of direct digital synthesis (DDS) to synthesize high-frequency analog signals has received much attention over the past decade. This technique allows modulation schemes such as FM and PM to be implemented with high fidelity using digital components. This paper investigates an improvement on the typical DDS approach of synthesizing the desired signal at an intermediate frequency. Instead, two quadrature baseband signals are generated, which are then mixed directly to the output center frequency. This method can be used to synthesize FM signals of arbitrarily high output frequency, using digital circuitry with considerably lower clock speeds View full abstract»

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  • Comparison of multiple-diffraction models for digital broadcasting coverage prediction

    Page(s): 221 - 226
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    This paper investigates and compares the efficiency and accuracy of existing multiple diffraction prediction techniques in real outdoor environments. Extensive comparisons are presented, including more than 20 000 path profiles. It is believed that this study will enable broadcasters to design and maintain broadcast networks with an accuracy commensurate with the highly demanding requirements for new and more efficient digital services. The comparisons involve the most well-known deterministic approaches (Deygout (1966), Causebrook (1971), Giovaneli (1984), Vogler (1982)) whose key feature is either the high accuracy of their predictions or their low computation times. However, a new slope-UTD based deterministic approach, developed recently by the authors, is found to provide the best compromise between computation speed and prediction accuracy View full abstract»

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  • Adaptive unequal error protection for subband image coding

    Page(s): 197 - 205
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    An adaptive subband image coding system is proposed to investigate the performance offered by implementing unequal error protection among the subbands and within the subbands. The proposed system uses DPCM and PCM codecs for source encoding the individual subbands, and a family of variable rate channel codes for forward error correction. A low resolution family of trellis coded modulation codes and a high resolution family of punctured convolutional codes are considered. Under the constraints of a fixed information rate, and a fixed transmission bandwidth, for any given image, the proposed system adaptively selects the best combination of channel source coding rates according to the current channel condition. Simulations are performed on the AWGN channel, and comparisons are made with corresponding systems where the source coder is optimized for a noiseless transmission (classical optimization) and a single channel code is selected. Our proposed joint source-channel systems greatly outperform any of the nonadaptive conventional nonjoint systems that use only a single channel code at all channel SNRs, extending the useful channel SNR range by an amount that depends on the code family. A nonjoint adaptive equal error protection system is considered which uses the classically optimized source codec, but chooses the best single channel code for the whole transmission according to the channel SNR. Our systems outperform the corresponding adaptive equal error protection system by at most 2 dB in PSNR; and more importantly, show a greater robustness to channel mismatch. It is found that most of the performance gain of the proposed systems is obtained from implementation of unequal error protection among the subbands, with at most 0.7 dB in PSNR additional gain achieved by also applying unequal error protection within the subbands. We use and improve a known modeling technique which enables the system to configure itself optimally for the transmission of an arbitrary image, by only measuring the mean of lowest frequency subband and variances of all the subbands View full abstract»

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  • Morphological segmentation of sport scenes using color information

    Page(s): 181 - 188
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    We propose a new method for segmenting image sequences in sports scenes containing brisk movement. An important feature of this method is the computation of color histograms in the areas for the turf, which is done interactively during rehearsal. Another important feature is automatic morphological segmentation during broadcast. The morphological segmentation consists of two operations: coarse segmentation by binary reconstruction based on the areas detected by thresholding the color histogram, and fine segmentation by watershed transformation with markers. It is shown that this new method achieves accurate segmentation in sport scenes View full abstract»

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  • OFDM system channel estimation using time-domain training sequence for mobile reception of digital terrestrial broadcasting

    Page(s): 215 - 220
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    A channel estimation technique using time-domain training sequence is investigated. It is demonstrated that this technique can estimate the channel status more accurately, under low C/N situations, than the conventional frequency domain technique using in-band pilots. A novel channel estimation and compensation scheme for a fast fading channel is developed for an OFDM system using time-domain training sequence. It is compared with the frequency domain pilot channel estimation scheme View full abstract»

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Aims & Scope

IEEE Transactions on Broadcasting covers the field of broadcast technology, including the production, distribution, transmission, and propagation aspects of broadcasting.

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Meet Our Editors

Editor-in-Chief
Yiyan Wu
Communications Research Ctr Canada