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Broadcasting, IEEE Transactions on

Issue 1 • Date March 1992

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Displaying Results 1 - 14 of 14
  • Comments on "The response of circuits to sine-squared pulses: the influence of cutoff" (by C.A. Siocos)

    Publication Year: 1992
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (21 KB)  

    A corrected version is given of equation 26, which is intended to describe the response of an ideal lowpass filter, in Appendix III of the above-titled work by Siocos (see ibid., vol.BC-17, p.19, Mar. 1971).<> View full abstract»

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  • A four-stage FM broadcast audio peak limiter

    Publication Year: 1992 , Page(s): 55 - 59
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    The design of a peak limiter processor for FM broadcast audio is described. The limiter has four gain control stages. The basic peak limiting function is performed in the first and second stages by a slow-attach-slow-release stage followed by a fast-attack-fast-release stage. Preemphasis control is performed in the third and fourth stages, which are part of a filter that emulates the transmitter preemphasis network. A peak clipper at the output of the preemphasis controller provides protection from overmodulation by short duration peaks that are not controlled by the four limiter stages View full abstract»

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  • A new, high efficiency, digital, modulation technique for AM or SSB sound broadcasting applications

    Publication Year: 1992 , Page(s): 38 - 42
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    Saturated pulse-width modulation (SPWM), a form of modulator control signal that uses a flash converter for analog-to-digital conversion, is discussed. SPWM is used to modulate high-power RF amplifiers. The operations of a flash converter, formed from a plurality of comparators, and a ring modulator, an address rotation circuit that performs a controlled sequence defining which comparator commands a particular power switch, are described View full abstract»

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  • DSC-HDTV broadcasting with upconverted NTSC video

    Publication Year: 1992 , Page(s): 7 - 11
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    A method of gradually introducing of simulcast digital spectrum-compatible (DSC)-HDTV broadcasting, thereby deferring a significant portion of the investment in new equipment, is described. Starting with a DSC-HDTV transmitter and antenna, all currently used National Television Systems Committee (NTSC) equipment continues to serve with the addition of an NTSC/DSC-HDTV scan converter, the upconverter. This unit is described in detail View full abstract»

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  • Hybrid clamping in NTSC digital video equipment

    Publication Year: 1992 , Page(s): 19 - 26
    Cited by:  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB)  

    Two algorithms that are suitable for deriving the blanking level of a National Television Systems Committee (NTSC) composite video signal are described. One method consists of averaging digitized color-burst samples taken from successive scan lines. A second method involves processing a group of samples taken from a single burst interval. Either algorithm used in a hybrid clamping arrangement results in automatic drift compensation and the ability to tie the back porch or sync tip to a predetermined digital output code. This aids in matching the analog signal to the input of the analog-to-signal (A/D) converter for maximum signal-to-noise ratio (SNR). In analyzing the effect of additive noise and timing jitter, it was found that both algorithms are, generally, more vulnerable than a conventional keyed clamper View full abstract»

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  • Performance of an error correction scheme for PAL-TV teletext

    Publication Year: 1992 , Page(s): 43 - 47
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    The shortened (272, 190) difference set cyclic code has been adopted for the Japanese teletext system using NTSC vertical blanking periods. This system is known as BEST (burst and random error correction system for teletext) for NTSC-TV systems. A powerful error correction system adopting the (272, 190) code for PAL-TV teletext signals is described. To compare the error correction characteristics of this system to those of WST (World System Teletext), transmission experiments were carried out multiplexing both data packets with different lines during the vertical blanking period of the same TV signals. The validity of applying BEST to the PAL-TV signals was confirmed, particularly when there is ghost interference View full abstract»

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  • A simplified HF field strength prediction procedure for India

    Publication Year: 1992 , Page(s): 75 - 79
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    Field strength measurements of several HF broadcast transmissions were made at New Delhi during 1987-1990 with a view to evolving a simple procedure for estimation of the skywave field strength in the HF bands (3-30 MHz). An attempt has been made using the measured field strength values to arrive at a single combined loss factor which can account for all the losses in excess of basic free space and ionospheric absorption losses. The present study has shown that a provision of 4 dB for transmission losses other than free space and ionospheric absorption losses can bring the predicted values closer to measured field strength values for single-hop circuits in India for about 50% of the cases, and 10 dB increases it to 90%. Transmission losses in general were found to be much higher during equinoctial months in India, particularly around the peak region of equatorial anomaly View full abstract»

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  • Transhorizon VHF TV signal propagation over mixed land-sea paths

    Publication Year: 1992 , Page(s): 33 - 37
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    The propagation characteristics of Rupavahini TV transmissions originating from Sri Lanka on channels 5 and 8 and monitored in southern India are studied. The receiving sites are chosen to provide mixed land-sea paths. The propagation characteristics of these mixed paths are influenced by sea-surface refractivity gradients and land-sea interactions. The analysis of the data indicates that different propagation mechanisms prevail for various percentages of time. Sometimes signal levels on the order of 10-dB below free space level are also observed, particularly in premonsoon months, which is due to the occurrence of ducting conditions prevailing in this region. Some observations of the distance dependence of the channel 5 signal show that the path loss increases by 10 dB for every 100 km of distance View full abstract»

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  • Pilot tone aided QPRS systems for digital audio broadcasting

    Publication Year: 1992 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    For fast fading channels, a spectrally efficient technique than can achieve more than 2 b/s/Hz with a built-in fade canceler is proposed. Recent studies show that fading in digital mobile communications can be canceled by adding redundant bits to the customer data or with pilot-aided techniques. This concept is extended to a more spectrally efficient class-IV quadrature partial response signaling (QPRS) system. However, in such schemes if the pilot is corrupted by the phase noise caused by the pilot-data interference, the fade cancellation will not effectively remove the error floor. The class-IV system has an inherent advantage in that it has a spectral null at DC and a low energy content at the ends of the band. Such systems also have a higher speed tolerance. It is shown that a small bandwidth around DC can be vacated to insert the pilot. Preliminary results show that residual error floor can be reduced from 10-2 to 10-5 in fast fading channels View full abstract»

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  • Will terrestrial broadcasting survive the HDTV standard?

    Publication Year: 1992 , Page(s): 69 - 74
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    Key analyses and specifications that the author asserts should have been part of the precertification process for HDTV systems are outlined. As part of the current precertification process, estimates for the channel and equipment impairments and the associated power penalties in the C/N (carrier-to-noise) are not required, the range of BER (bit error rate) for a given EFH (error free hours) is not specified, and the expected spectral spreading into adjacent channels due to the nonlinear power amplifier is hardly mentioned. The problems with the ATTC laboratory tests and field tests are discussed View full abstract»

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  • A voltage-matching method for feeding antenna arrays

    Publication Year: 1992 , Page(s): 27 - 32
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    A method for feeding antenna arrays is presented. Each element of the array is connected with transmission line sections. The first two sections are connected to a common point where the voltage from both sections is the same. The common point is connected with a new transmission line which is also doing the same with the third section. The procedure is continued until the last common point will be connected to a single source. A formulation for the antenna currents as a function of the frequency is also given. Some examples show the applicability of the method View full abstract»

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  • Automatic identification of impairments caused by intermodulation distortion in cable television pictures

    Publication Year: 1992 , Page(s): 60 - 68
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (604 KB)  

    The authors study the feasibility of automatically monitoring a television picture for the purpose of knowing whether or not impairments resulting from intermodulation beats are present. They develop a mathematical model for the intermodulation beats and show that the theoretical results confirm the experimental ones. These results show that by using the two-dimensional discrete Fourier transform of a picture the automatic detection and recognition of intermodulation distortion is feasible. The results demonstrate, contrary to common belief, that it is possible to monitor the signal in a nonintrusive fashion View full abstract»

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  • Performance evaluation of a teletext system

    Publication Year: 1992 , Page(s): 48 - 54
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    Four parameters are defined to measure the performance of a teletext system, namely, the probability of delivering a message within specified time, the transmission efficiency, the average number of errors per page, and the throughput. Each of them is derived and computational results are presented taking the UK teletext system as an example. These parameters are compared in their ability to characterize the performance of the teletext system View full abstract»

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  • An HDTV high performance HARP camera-one inch HDTV HARP camera

    Publication Year: 1992 , Page(s): 12 - 18
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    A high-performance high-definition television camera is described. This camera, which employs a recently developed 1-in HARP pickup tube, provides high-quality pictures and provides 32 times maximum sensitivity compared with an HDTV camera using Saticon tubes. This camera's amplitude response is more than 40% at 800 TV lines. Some unique techniques are developed to correct misregistration precisely and provide fine focusing 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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Editor-in-Chief
Yiyan Wu
Communications Research Ctr Canada