会员体验
专利管家(专利管理)
工作空间(专利管理)
风险监控(情报监控)
数据分析(专利分析)
侵权分析(诉讼无效)
联系我们
交流群
官方交流:
QQ群: 891211   
微信请扫码    >>>
现在联系顾问~
热词
    • 19. 发明授权
    • Interference cancellation system for CATV return transmissions
    • 用于CATV返回传输的干扰消除系统
    • US5742591A
    • 1998-04-21
    • US473755
    • 1995-06-07
    • Nageen HimayatCharles A. Eldering
    • Nageen HimayatCharles A. Eldering
    • H04N7/10H04N7/173H04B3/20
    • H04N7/102H04N7/17309
    • A CATV interference cancellation system reduces the presence of undesirable narrowband interference that corrupts return signal transmissions. The cancellation system first acquires a reference signal that contains components related to the interference present in the return signal. The reference signal is processed to derive estimates of the interference components appearing in the return signal and a cancellation signal is generated. The interference cancellation signal is then combined with the return signal, thereby reducing the interference components present in it. The interference cancellation system is deployed at a CATV headend and time division multiple access techniques (TDMA) are used for return transmission. The reference signal is derived from monitoring time slots within a TDMA frame that contain predetermined transmission data. Preferably the predetermined data is the absence of data resulting in an idle time slot. These time slots may be temporarily idle, or may deliberately be left unused to provide a window to a "noise-only" component of the return path signal. The signal thus obtained is passed through the same RF processing stage as the composite return signal and subsequently sampled and digitized. Thereafter, spectrum estimation techniques are applied to the samples of the signal to determine the frequencies of the interfering signals. Once an estimate of the interference frequencies is obtained from the spectrum, the reference signal comprising the same frequencies may be synthesized.
    • CATV干扰消除系统减少了不利的窄带干扰的存在,破坏了返回信号传输。 取消系统首先获取包含与返回信号中存在的干扰有关的分量的参考信号。 对参考信号进行处理以导出出现在返回信号中的干扰分量的估计,并且产生消除信号。 然后将干扰消除信号与返回信号组合,从而减少存在于其中的干扰分量。 干扰消除系统部署在CATV前端,时分多址技术(TDMA)用于返回传输。 该参考信号源自包含预定传输数据的TDMA帧内的监视时隙。 优选地,预定数据是不存在导致空闲时隙的数据。 这些时隙可能暂时空闲,或者可能被故意地留下来,以向返回路径信号的“仅噪声”分量提供窗口。 如此获得的信号通过与复合返回信号相同的RF处理级,并随后进行采样和数字化。 此后,将频谱估计技术应用于信号的样本以确定干扰信号的频率。 一旦从频谱获得干扰频率的估计,可以合成包括相同频率的参考信号。