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1. 发明授权

US4665427A Method and apparatus for converting C-MAC television signals for transmission over a limited bandwidth medium 失效
标题翻译：用于转换C-MAC电视信号以在有限带宽介质上传输的方法和装置
公开(公告)号：US4665427A
公开(公告)日：1987-05-12
申请号：US585705
申请日：1984-03-02
申请人： John C. Beckley , Peter R. Brennand , Bruce Murray
发明人： John C. Beckley , Peter R. Brennand , Bruce Murray
IPC分类号： H04N7/06 , H04N7/083 , H04N11/08 , H04N11/00
CPC分类号： H04N11/08 , H04N7/06 , H04N7/083
摘要： A wide-band frequency modulated DBS signal of the type having time sequential compressed chrominance and luminance (video) components is received by an aerial (1), frequency converted in a down converter (2) and applied to the input (4) of a conversion unit. The conversion unit has a tuner (5), i.f. stage (9,10) and a frequency demodulator (11) to produce baseband video which is applied after de-emphasis at (12) to a modulator (27) where the video is amplitude modulate onto a vision carrier from an oscillator (28). The modulated carrier is applied through a vestigial sideband filter (29) and an adder (30) to an output (31). Sound/data bursts present in the DBS signal are recovered in a stage (13) and processed in a processor (14) where the sound/data bursts are expanded to occupy approximately a line period at a bit rate which is an integral sub-multiple of the bit rate for the sound/data bursts in the received DBS signal. The expanded sound/data and clock frequency are digitally modulated in a modulator (32 ) onto a sound carrier from an oscillator (33), the modulated sound carrier being applied through a bandpass filter (34) and the adder (30) to the output (31). The output (31) is connected to a cable distribution system for which the narrow band signals produced by the conversion unit are suited as such systems cannot cope with high bit-rates. The processing of the sound/data bursts such that their bit rate is substantially reduced also simplifies the handling and demodulation processes for these bursts.
摘要翻译：具有时间顺序压缩色度和亮度（视频）分量的类型的宽带调频DBS信号由天线（1）接收，在下变频器（2）中进行频率转换，并被施加到输入（4）转换单位。转换单元具有调谐器（5），即（9,10）和频率解调器（11），以产生在（12）的去加重之后施加到调制器（27）的基带视频，其中视频被振幅调制到来自振荡器（28）的视频载波上，。调制载波通过残留边带滤波器（29）和加法器（30）施加到输出端（31）。存在于DBS信号中的声音/数据突发在阶段（13）中被恢复，并在处理器（14）中进行处理，其中声音/数据脉冲串被扩展以占据大约一个行周期，比特率是整数子倍数的接收到的DBS信号中的声音/数据脉冲串的比特率。扩展的声音/数据和时钟频率在调制器（32）中从振荡器（33）被数字调制到声音载波上，经调制的声音载波通过带通滤波器（34）和加法器（30）施加到输出端（31）。输出（31）连接到由转换单元产生的窄带信号适合的电缆分配系统，因为这样的系统不能应付高比特率。声/数据脉冲串的处理使得它们的比特率显着降低也简化了这些脉冲串的处理和解调处理。

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