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本文是描述为探讨高清晰度电视系统的图像质量,及其设计问题而试制的扫描行为1125行的宽带轮廓补偿器。轮廓补偿器的性能主要决定于把行视频信号延迟一行的延时线性能。作为1125行制式的送像装置的视频带宽,当考虑到图像宽高比时就要有30Mc,以前的一行延时线(带宽约±10Mc)就不适用了。因此,这次使用新换能器(铌酸锂—LiNbO_3)研制了中心频率为50Mc,带宽为±25mc的延时线。另外,为补偿中心频率的低点,使用伪信号-40db以下的平衡调制和由同步检波电路产生的载频60Mc的残留边带传送方式,这样就得到30Mc-3db,信噪比为50db(p-p/rms),伪信号-30db以下的一行延时线。采用这种一行延时系统作成的轮廓补偿器性能与单个的一行延时系统性能基本相同。根据实际图像的鉴定结果,被确认为本补偿器对改善1125行高清晰度电视系统的清晰度是极为有效的,且十分实用。
This article describes a wideband contour compensator for an 1125-line scan behavior trial to explore the image quality and design issues of high-definition television systems. The performance of the contour compensator is mainly determined by the delay line performance that delays the line video signal by one line. As the 1125-line video feed device, the video bandwidth, when taking into account the aspect ratio than when there must be 30Mc, the previous line delay line (bandwidth of about ± 10Mc) is not applicable. Therefore, this time using a new transducer (lithium niobate - LiNbO_3) developed a center frequency of 50Mc, a bandwidth of ± 25mc delay line. In addition, in order to compensate for the low center frequency, the use of counterfeit signals below -40db balanced modulation and synchronous detection circuit generated by the carrier 60Mc carrier sideband transmission, so get 30Mc-3db, signal to noise ratio of 50db (pp / rms), a line of delay below -30db. The performance of the contour compensator made using this one-line delay system is basically the same as that of a single one-line delay system. According to the actual image of the identification results, was identified as compensator to improve the clarity of 1125 high-definition television system is extremely effective, and very practical.