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1. 发明授权

US4290090A Apparatus for and method of noise-free detection of inter-feature pauses to control selective replay in tape recording/reproduction systems 失效
标题翻译：用于无噪声检测特征间暂停以控制磁带记录/再现系统中的选择性重放的装置和方法
公开(公告)号：US4290090A
公开(公告)日：1981-09-15
申请号：US133821
申请日：1980-03-25
申请人： Ryuji Yamamoto , Kiyotaka Ohsawa
发明人： Ryuji Yamamoto , Kiyotaka Ohsawa
IPC分类号： G11B15/087 , G11B15/02 , G11B20/24 , G11B27/22 , G11B15/16 , G11B15/52 , G11B19/10
CPC分类号： G11B20/24 , G11B27/22
摘要： Recorded features on a recording medium have inter-feature pauses which must be reliably detected in order to control the selective replay of the features. Certain noise signals located within an inter-feature pause complicate the detection of the latter. These noise signals include low-frequency signals which have high voltage levels at playback speed, and middle- and high-frequency signals which have high voltage levels at fast forward or rewind speed. These high voltage levels of the noise signals could be mistaken for audio signals. A signal-processing circuit filters the noise signals from the audio signals. A control circuit changes the impedance of the signal-processing circuit such that the signals are filtered according to a first predetermined filter characteristic when the recording medium advances at playback speed, and according to a different second predetermined filter characteristic when the recording medium advances at fast forward or rewind speed. The filter characteristics attenuate the high voltage levels of the noise signals to low voltage levels, thereby preventing the noise signals from being mistaken for audio signals at the playback or fast forward or rewind speeds.
摘要翻译：记录介质上记录的特征具有必须可靠检测的特征间暂停，以便控制特征的选择性重放。位于特征间暂停中的某些噪声信号使后者的检测复杂化。这些噪声信号包括在重放速度下具有高电压电平的低频信号，以及在快进或快退速度下具有高电压电平的中频和高频信号。这些高电平的噪声信号可能被误认为音频信号。信号处理电路对来自音频信号的噪声信号进行滤波。控制电路改变信号处理电路的阻抗，使得当记录介质以重放速度前进时，根据第一预定滤波器特性对信号进行滤波，并且当记录介质快速前进时根据不同的第二预定滤波器特性前进或后退速度。滤波器特性将噪声信号的高电压电平衰减到低电压电平，从而防止噪声信号在播放或快进或快退速度时被误认为音频信号。

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