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公开(公告)号：EP0361452A2
公开(公告)日：1990-04-04
申请号：EP89117885.7
申请日：1989-09-27
发明人： Matsumoto, Tokikazu
IPC分类号： H03G3/20
CPC分类号： H03G3/20
摘要： A digital automatic gain control apparatus designed to control gain in such a way that when an analog video signal is converted into digital signals for processing, the input of the A-D converter (2) is maintained at a fixed level, and after the analog signal has been converted into digital form, the output of the digital system circuit is also maintained at a fixed level. In this apparatus, an input signal is passed through an analog variable gain amplifier, the signal is converted into digital form, the output of an A-D converter is passed through a digital variable gain amplifier (3). The amplitude level of the output of the digital variable gain amplifier (3) is detected by an amplitude detecting means and is controlled so as to be equal to a specified reference value. At this time, the analog variable gain amplifier (1) is controlled so that the level of the control signal for controlling the digital variable gain amplifier (3) is equal to a specified reference value, thereby maintaining the input signal of the A-D converter (2) at a fixed level. Gain control of the analog signal system and the digital signal system, before and after the A-D converter (2) is effected by a single amplitude detecting means.
摘要翻译： 一种数字自动增益控制装置，被设计成以这样的方式控制增益，使得当模拟视频信号被转换成用于处理的数字信号时，AD转换器（2）的输入被保持在固定电平，并且在模拟信号具有 被转换为数字形式，数字系统电路的输出也保持在固定的水平。 在该装置中，输入信号通过模拟可变增益放大器，信号被转换为数字形式，A-D转换器的输出通过数字可变增益放大器（3）。 数字可变增益放大器（3）的输出的幅度电平由振幅检测装置检测，并被控制为等于指定的参考值。 此时，模拟可变增益放大器（1）被控制，使得用于控制数字可变增益放大器（3）的控制信号的电平等于指定的参考值，从而保持AD转换器的输入信号（ 2）在一个固定的水平。 A-D转换器（2）之前和之后的模拟信号系统和数字信号系统的增益控制由单个振幅检测装置实现。
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公开(公告)号：EP0197767A3
公开(公告)日：1988-07-27
申请号：EP86302468
申请日：1986-04-03
IPC分类号： H04N05/91
摘要： A video signal processing apparatus incorporates a 1 H or 2H (H: horizontal synchronization period) delay circuit (3). The output of the delay circuit (3) is fed back to the input thereof so as to average the noise, thus raising the signal S/N ratio. The feedback line includes a nonlinear processing circuit (8) with a small gain when the signal input has a low vertical correlation, whereby the signal S/N ratio is improved without causing delay of the colour signal in the vertical direction nor deterioration of resolution of the luminance signal.
摘要翻译： 视频信号处理装置包含1H或2H（H：水平同步周期）延迟电路（3）。 延迟电路（3）的输出反馈到其输入端，以平均噪声，从而提高信号S / N比。 反馈线包括当信号输入具有低垂直相关性时具有小增益的非线性处理电路（8），由此提高信号S / N比而不导致垂直方向上的彩色信号的延迟， 亮度信号。
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公开(公告)号：EP0164274A3
公开(公告)日：1987-01-28
申请号：EP85304060
申请日：1985-06-07
IPC分类号： H04N09/68
CPC分类号： H04N9/793 , H04N9/68 , H04N9/7904
摘要： A digital chrominance signal processing system comprises a variable gain amplifier (11) for gain control of a carrier chrominance signal; an A/D converter (12) for effecting analogue/digital conversion of the output of said variable gain amplifier; a demodulator (13) for demodulating the output of said A/D converter into two chrominance difference signals (R-Y, B-Y); a computing circuit (15) for computing the amplitude of the burst signal of said carrier chrominance signal from said two chrominance signals; and a control circuit (21) for producing a signal for controlling the gain of said variable gain amplifier by the output of said computing circuit, whereby the gain control is prevented from erroneous operation even when the demodulating axis of the demodulator is not in agreement with the burst phase.
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公开(公告)号：EP0168157A2
公开(公告)日：1986-01-15
申请号：EP85303977.4
申请日：1985-06-05
发明人： Matsumoto, Tokikazu
IPC分类号： H04N9/64
摘要： A digital chrominance signal processing system performs control in such a manner to make the phase difference between the burst signal and the clock always zero and comprises: an A/D converter (11) for effecting analogue/ digital conversion of a video signal containing a carrier chrominance signal; a frequency controllable variable frequency oscillator (24) for generating a clock to be given to said A/D converter; a phase comparator (13) for comparing the output of said A/D converter with the phase of said clock; a computing circuit (14) for computing the absolute value and sign of the output signal of said phase comparator during a burst period; and two current sources (18,19) of current outflow type and current influx type whose current values are controlled by the absolute value output (16) of said computing circuit (14) and turned on/off respectively by the sign output (15) of said computing circuit (14), wherein output terminals of said current outflow type current source and said current influx type current source are connected with each other and outputs of said current sources control said variable frequency oscillator through a low pass filter (22,23).
摘要翻译： 数字色度信号处理系统以这样一种方式执行控制，使脉冲串信号和时钟之间的相位差始终为零，并包括：A / D转换器（11），用于对包含载波的视频信号进行模/数转换 色度信号 用于产生要被提供给所述A / D转换器的时钟的频率可控变频振荡器（24）; 相位比较器（13），用于将所述A / D转换器的输出与所述时钟的相位进行比较; 计算电路（14），用于在脉冲串周期期间计算所述相位比较器的输出信号的绝对值和符号; 以及电流流出型和电流流入型的两个电流源（18,19），其电流值由所述计算电路（14）的绝对值输出（16）控制并通过符号输出（15）分别导通/截止， 的所述计算电路（14），其中所述电流流出型电流源和所述电流涌流型电流源的输出端彼此连接，并且所述电流源的输出通过低通滤波器（22,23 ）。
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公开(公告)号：EP0102809A1
公开(公告)日：1984-03-14
申请号：EP83304888.7
申请日：1983-08-24
IPC分类号： H04N5/783
摘要： A magnetic reproducing apparatus which has two main rotatable heads (M M 2 ) having different azimuth angles and two auxiliary rotatable heads (S 1 , S 2 ) having different azimuth angles. When a magnetic tape (6) is played back at a speed different from that at which was recorded, playback output signals from the main and auxiliary rotatable heads are switched over to replace a reduction in the outputs from the main rotatable heads (M 1 , M 2 ) with the outputs from the auxiliary rotatable heads (S 1 , S 2 ) to produce a combined playback output signal. The combined playback output signal is passed through a variable delay line (30,71) having a delay time varied by an output from a detector cricuit (72) which detects variations in horizontal synchronous signal intervals of the combined playback output signal. This varied delay time of the variable delay line can eliminate any skew distortions which would appear on a displayed image on the screen due to the variations in horizontal synchronous signal intervals of the combined playback output signal.
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