An ADPCM Receiver for NTSC Composite Video Signals

An ADPCM codec for carrying one broadcast quality NTSC color TV channel at a bit rate of 42.9 Mb/s has been proposed. The system uses 3 fsc sampling, adaptive intrafield contour prediction, adaptive quantization., 4/8-bit dual length coding, and horizontal blanking interval suppression techniques. The receiver of.the video codec is designed and implemented in ECL for recovery of the original signal. The receiver accepts.a 42.9 Mb/s serial data stream with a synchronous clock from the transmitter. The receiver detects the line synchronization code, demultiplexes the audio signal and video signal, and generates the horizontal blanking patterns which have been removed at the transmitter side. The 4/8-bit dual length code is decoded and fed to the ADPCM reconstruction loop to obtain the reconstructed active video signal. The generated horizontal blanking pattern is multiplexed with the reconstructed video=signal and sent through a D/A converter to form the reconstructed analog NTSC composite video signal.     

Universal digital TV codec—unicodec

The UNICODEC, developed under the INTELSAT R & D Program, is a TV codec which can transmit and receive any standard signal of NTSC, PAL, or SECAM, by using 15 Mb/s or 30 Mb/s transmission rates (switchable) with two high quality sound channels and one voice circuit. These rates include rate 239/255 BCH FEC for video information. The codec uses the 4:2:2 digital interface for component coding based on CCIR Recommendation 601. The UNICODEC can provide the flexibility to deal with the composite coding now needed in mixed analogue/digital networks, but can also handle either composite NTSC, PAL, SECAM or MAC (multiplexed analogue components), or digital component signals (Y, R-Y, B-Y) in the future. The key technique used here is called MAP (median adaptive prediction) coding, which is one of the adaptive DPCM methods for accurate and simple control in high quality TV transmission; one prediction out of three (interframe, intrafield or interfield) is transmitted without the need for many control bits. There is also a refresh mode for burst error or synchronization recovery. The UNICODEC is expected to provide double capacity with higher quality pictures compared to conventional analogue transmission (FM in 18 MHz). Alternatively, smaller size antennas may be used. This paper describes the objectives of the development of the UNICODEC, its main features and results of field tests.     

32 Mbit/s Transmission of NTSC Color TV Signals by Composite DPCM Coding

A composite DPCM coding System was developed, which is capable of coding and transmitting an NTSC color TV signal without component separation at a 32.064 Mbit/s rate. The DPCM prediction method used is based on the algorithm that a luminance component prediction valuehat{y}and a carrier chrominance component prediction valuehat{c}are calculated individually, and then the composite signal prediction valuehat{x}is determined byhat{x} = hat{y} + hat{c}. In order to utilize horizontal blanking (HBL) intervals for transmitting active video signals,HBL signals are not transmitted in each line but their representative signals are transmitted once a frame during a vertical blanking interval. A dual word-length coding and quantizing method is adopted, which uses 4 bit and 8 bit words with average word-lengths of 4.4 bits/sample. Codec equipment was fabricated, and coding and transmitting experiments were conducted, using NTT's PCM-100 M digital repeatered line. Experimental results show that this composite DPCM coding system can be employed for digital transmission of NTSC color TV signals, such as color ITV signals, at a 32.064 Mbit/s rate.     

浅谈电视信号发生器PM5415的校准

根据信息产业部电子601计量站和信息产业部电子203计缱站起草的JJF1235—2010《电视视频信号发生器校准规范》,制式为PAL、NTSC、SECAM的模拟电视信号发生器都能用此校准规范进行校准,该文根据此校准规范埔VM700视频分析仪校准FLIJKE公司生产的璎号为PM5415的电视信号发生器。     

Digital Separation and Reconstruction of NTSC Signals

A new digital method for separation and reconstruction of NTSC color TV signals is described. Digital conversion between an NTSC signal and its baseband component signals is performed at a sampling rate of(12/5)f_{sc} simeq 8.59MHz (fsc: the color subcarrier frequency), which is lower than the conventionally used3f_{sc}or4f_{sc}sampling rate. Since this lowered sampling rate satisfies the Nyquist condition for NTSC signals, the proposed digital method can provide an effective technique for the component coding of NTSC signals. Simulation results have shown that, with this method, no visible picture quality degradations can be observed for either the color bar signal or SMPTE Pictures.     

A CCD image sensor with 768 × 490 pixels

A ⅔-in 768(H) × 490(V) element interline CCD image sensor has been successfully developed. The device adopts a vertical overflow drain principle, a buried,channel amplifier, three-level polysilicon technology, and 1.5-µm-rule fine-pattern process. The device operates with an NTSC format. The 560 TV lines limiting resolution is obtained in the horizontal direction. No significant loss in transfer efficiency is observed in the horizontal register, even at the 14.32 MHz clock rate. Optimal photosensitivity spectrum response is obtained and the peak response appears at 550 nm. The noise equivalent signal is reduced to 48 electrons, using correlated double sampling. Then, the dynamic range reaches 68 dB. The correlated double sampling, combined with buried-channel amplifier technology is found to be also effective for great reduction in horizontal line noise.     

High Definition NTSC Broadcast Protocol

This paper describes a new process referred to as HD-NTSC?. This signal has all the appearances of a conventional NTSC signal, and can be edited, stored, transmitted, and received by conventional NTSC equipment. A receiver constructed to interpret the HD-NTSC protocol will be able to build an ID-NTSC image having substantially improved resolution in both the vertical and horizontal axes for those parts of the imnage that are nearly stationary over time. Those parts of the image exhibiting motion will show resolution equivalent to a conventional top-quality NTSC picture. The HD-NTSC receiver will also display the image at 60 frames per second, eliminating most interlace and flicker defects. An optional technique widens the image aspect ratio and creates bandwidth within the original NTSC standard large enough to transmit a digitally-encoded stereo audio signal to match the improved visual characteristics.     

基于VX1937的VGA／TV转换器的设计与实现

为了将PC机输出的VGA视频信号转换成适合普通电视标准的电视信号,设计了一款基于VX1937数字视频处理器的VGA/TV转换器。该系统根据VGA信号的刷新频率对一帧VGA运行扫描视频信号进行A／D采样,并经过缓冲、箝位,缓存在外部SDRAM中,经奇偶场重组和场内的数据插值处理后,在输出端经过D／A转换器转换为模拟视频信号。与传统的转换器相比．该系统支持多种分辨率,具有内建OSD功能。该系统具有无需软件支持、运行可靠、操作简单等特点。在飞机座舱VGA／TV转换器的设计实验中获得了质量较好的PAL制式标准电视视频信号。实验证明．该系统最高可将1024×768（60Hz）的真彩色逐行图像转换成NTSC或者PAL制式的视频信号,具有较高的应用价值．     

Interframe Coding for 4-MHz Color Television Signals

An interframe coding system is described which is capable of transmitting a 4-MHz National Television System Commission (NTSC) color television signal. 6.3 Mbit/s transmission gives acceptable picture quality for video telephone or conference TV use. The NTSC color television signal is converted into a timedivision multiplex (TDM) signal which is composed of time-compressed chrominance and luminance signal in sequence. This signal is encoded using a frame-difference coder of the kind that has been used for black-and-white television signals. A field-repeating technique is introduced into the coder, to prevent a buffer memory from overflowing and to improve picture quality. Statistical investigations show that the presence of the timecompressed chrominance signal gives less than 10 percent increase in the amount of information generated by picture movements; this increase scarcely affects the picture quality.     

A compatible high-resolution TV system for cablecasting

Cablecasting offers the possibility of a new and improved system of color television. New technology for wide bandwidth, for large displays, and better signal transmission systems make it desirable to improve on the National Television System Committee (NTSC) system which has served so well for over-the-air transmissions. In this paper, a system is suggested with which a subscriber owning a present TV receiver Will continue to get the same picture quality as he does now. New receivers can be designed to provide substantially improved resolution and better color reception. The system uses two adjacent 6-MHz channels for each one now used. The upper channel is standard NTSC, while the lower channel is filled with a lower sideband that permits a 7-MHz video response, Present receivers use the upper channel, while new receivers will use signals from both channels.     

A 32 Mbit/s Component Separation DPCM Coding System for NTSC Color TV

A component separation DPCM Coding system is described which is capable of transmitting a 4 MHz NTSC color TV signal with broadcast quality at a 32.064 Mbit/s rate. The input NTSC color TV signal is first separated into a luminance componentYand two chrominance componentsIandQ. Then, these three components are converted into a TDM-PCM color signal, whereIandQof only odd lines are transmitted and samples in horizontal blanking intervals ofY,I,andQare removed, in order to reduce the transmission rate. This TDM-PCM signal is encoded by a single DPCM coder, which employs a two-dimensional prediction method and a dual word-length coding method. For theYsignal, 4 bit and 8 bit code words are assigned to 29 quantizing levels. For bothIandQsignals, 3 bit and 6 bit code words are assigned to 13 quantizing levels. Coding experiment results show that this coding system is promising for application to broadcast color TV signal transmission at a 32.064 Mbit/s rate.     

Extended definition TV over an analog FM satellite channel

The performance of several extended definition TV (EDTV) formats are compared in terms of signal-to-noise ratio (SNR) operation in an analog FM satellite channel. The formats considered are the National Television System Committee (NTSC), extended NTSC (ENTSC), multiplexed analog components (MAC), and extend MAC (EMAC). These formats are compared in terms of SNR above and below the FM threshold. Analytically derived curves which show the luminance and chrominance SNR as a function of horizontal resolution for the above-threshold operation are presented. The effect of group delay on the composite video formats is determined for an actual satellite channel. The below-threshold performances for NTSC and MAC are compared in the luminance channel     

Digital TV Receiver for NTSC Color TV Signals with Dual Word-Length DPCM Coding

A video codec system for carrying one broadcast quality NTSC color TV channel at a rate of 42.935 Mbits/s has been proposed. The receiver of the video codec system is developed for recovery of the original signal. The receiver accepts a 42.935 Mbits/s serial TDM data stream with a synchronous clock from the Transmitter. The receiver detects the unique sync code and inserts a horizontal blanking pattern which has been removed from the transmitting data. The audio and video data are separated at the outputs of the demultiplexer. The 4/8 bit dual length code word of the video data is smoothed out by a buffer memory and fed to the DPCM reconstruction loop. The analog NTSC color video signal as well as the audio signal are reconstructed after the D/A conversion. This paper describes the design and development of the receiver portion (Fig. 1) of the codec which is capable of transmitting'one color signal at broadcast standards on a T3 digital link.     

数字电视视频标准基本参数的诠释

比较了数字电视视频的格式与制式的概念、标准与规范的概念以及数字电视清晰度(分辨率)的概念，指出数字电视的分辨率不同于显像管本身的分辨率；诠释了数字电视的扫描格式、宽高比以及编码方式等基本参数，详尽地论述了数字视频信号编码中的复合编码和分量编码、数字视频传输中的信源编码和信道编码。     

Compatible High Definition Television Broadcast Systems

This paper describes NTSC compatible HIDTV systems with incremental improvement potential. The systems are capable of increased horizontal and vertical resolution, reduced crosstalk between the components, and a wide aspect ratio. Experimental results on a split-luminance system show that 600 lines of horizontal resolution are achieved after the luminance signal band has been divided at the encoder and recombined at the decoder. Spatial splitting of the picture is employed to increase the aspect ratio. A low cost HDTV system is also presented that uses a modulated-signal combination. With this system, considerable simplification is possible with a slight reduction in resolution. All proposed systems are fully NTSC compatible and utilize two standard 6 MHz channels for transmission. The improvements can be realized incrementally because of their downward compatibility at the receiver.     

WHT-based composite motion compensated NTSC interframe directcoding

The motion compensated interframe differential pulse code modulation (DPCM) and discrete cosine transform (DCT) hybrid (MC DCT) coding was nominated as a standard scheme for component TV signals by ISO and ITU-R. However, in cases where an NTSC composite TV signal is used such as the United States and Japan, applying the MC DCT scheme with its luminance/chrominance separating and composing process causes unavoidable quality degradation. The reason for this additional process required for MC DCT is that a composite TV signal presents a “color subcarrier phase shift problem” in which the color subcarrier phase varies between a coding block and reference block according to the motion vector. In this paper, we propose a Walsh Hadamard transform (WHT)-based composite motion compensated NTSC interframe direct coding scheme. In this scheme, phase shifts of a color subcarrier and modulated chrominance components between a coding block and reference block can be effectively compensated by a simple process of coefficient permutation and polarity changes of several pairs of WHT coefficients to which 100% of the subcarrier energy and most of the modulated chrominance component's energy are packed. In the motion compensated DCT scheme, however, the energy of the color subcarrier and modulated chrominance components are spread over too many coefficients and a pair-based coefficient handling rule is not given to solve this problem. This paper demonstrates that the proposed scheme provides higher coding performance for a composite NTSC signal than does the motion compensated DCT scheme with its luminance/chrominance separating and composing process     

浅议电视信号的数字化与码率压缩

介绍了电视信号数字的优点、含义和彩色电视信号的编码标准——CCIR601建议，讨论了电视信号常用的码率压缩技术。     

15/30 Mbit/s Universal Digital TV Codec Using a Median Adaptive Predictive Coding Method

This paper describes a 15/30 Mbit/s TV codec with a new approach to high-efficiency coding for TV signals, i.e., median adaptive prediction. The 15/30 Mbit/s codec, commonly applicable to NTSC, PAL, and SECAM (525/60 and 625/50) systems, uses adaptive prediction incorporating a motion-compensated interframe, an interfield, and an intrafield predictor. Its performance for digital transmission is presented. This universal codec is designed, based on CCIR recommendations concerning digital TV coding parameters for studios (Rec. 601) and general principles on long-distance digital TV transmission (Rec. 604). A field trial of 15 Mbit/s digital TV transmission using this codec between earth stations with a 30 m diameter antenna and a 5 m diameter antenna is reported.     

具有视频动态校正功能的TFT-LCD驱动IC

介绍一种具备视频动态校正功能的TFT—LCD驱动IC设计,剖析电路原理,采用双极工艺流片,具备多制式NTSC／PAL视频信号处理及RGB解调功能,根据不同制式选择相应的解调电路,NTSC／PAL都为正交幅度平衡调制信号,所以解调时都需要产生正交基准载波信号,载波的频率及相位的锁定主要依靠内部锁相环路,锁相后的载波信号进入正交平衡解调器解调出相应的色差信号。NTSC制式下陷波频率点为3．58MHz,此制式需要特设TINT调节电路;PAL制式下陷波频率点为4．43MHz,此制式解调需要产生0°及＋90°载波;色度信号经延时解调器,也称梳状滤波器分离出两个色度分量FU和±FV。在设计中,充分结合、比较LCD与CRT驱动的不同之处,对R、G、B三基色信号进行校正处理,最终使还原到LCD显示屏的画面在亮度、对比度、色度等各方面都达到最佳效果。