公开(公告)号：US5390213A

公开(公告)日：1995-02-14

申请号：US927512

申请日：1992-09-21

申请人： Eugene M. O'Donnell

发明人： Eugene M. O'Donnell

IPC分类号： G11B20/06 ,  H03C3/00 ,  H04N5/922 ,  H04N9/80 ,  H03K7/08

CPC分类号： H04N9/80 ,  H03C3/00

摘要： A digital synthesizer for record circuitry of, e.g., a VCR, is supplied with digital samples representing a video signal. A calculator stage, responsive to the digital samples calculates a sequence of pulse periods defining a pulse duration modulated signal that represents FM modulation of a carrier by the video signal. An output sample generating stage operates on the sequence of pulse periods for generating a sequence of digital output samples which is converted in a digital-to-analog converter to the FM modulated video signal for subsequent recording on tape.

摘要翻译： PCT No.PCT / US91 / 03811 Sec。 371日期：1992年9月21日 102（e）日期1992年9月21日PCT 1991年5月30日提交PCT公布。 出版物WO91 / 20124 PCT 日期为1991年12月26日。用于例如VCR的记录电路的数字合成器被提供有表示视频信号的数字样本。 响应于数字样本的计算器级计算定义表示由视频信号对载波的FM调制的脉冲持续时间调制信号的脉冲周期序列。 输出采样产生级对脉冲周期序列进行操作，用于产生数字输出采样序列，其在数模转换器中转换为FM调制视频信号，以便随后在磁带上记录。

公开(公告)号：US5355227A

公开(公告)日：1994-10-11

申请号：US832911

申请日：1992-02-07

申请人： Jung W. Ko ,  Christopher H. Strolle

发明人： Jung W. Ko ,  Christopher H. Strolle

IPC分类号： H04N5/922 ,  G11B20/10 ,  H04N5/92 ,  H04N5/93 ,  H04N9/797 ,  H04N5/76

CPC分类号： H04N5/93 ,  H04N9/7976

摘要： An apparatus and a method for reproducing television images from recordings of folded-spectrum video signals uses a zero-crossing detector to convert an FM signal encoding folded-spectrum luminance signal to a PPM signal having the folded-spectrum luminance signal in its baseband, accompanied by the harmonics of the FM carrier and their respective sidebands. The PPM signal is digitized by an analog-to-digital converter, after passage through an anti-aliasing filter that is used to suppress only higher frequencies that would otherwise be sampled at less than Nyquist rate during digitization. Except for this anti-aliasing filtering, the suppression of the harmonics of the FM carrier and their respective sidebands is deferred until after digitization. Linear-phase digital filtering is then used to suppress the harmonics of the FM carrier and their respective sidebands, and the folded-spectrum luminance signal supplied in response to this digital filtering is unfolded to restore it to its original full bandwidth. This procedure permits the group delay characteristic below the folding-carrier frequency to be kept constant, thereby avoiding phase error as would interfere with the unfolding of the folded signal into the original full bandwidth.

摘要翻译： 一种用于从折叠频谱视频信号的记录中再现电视图像的装置和方法使用过零检测器将编码折射谱亮度信号的FM信号转换为在其基带中具有折射谱亮度信号的PPM信号，伴随着 通过FM载波及其各自的边带的谐波。 在通过抗混叠滤波器之后，PPM信号由模数转换器数字化，该抗混叠滤波器仅用于抑制在数字化期间以小于奈奎斯特速率采样的较高频率。 除了这种抗混叠滤波之外，FM载波及其相应边带的谐波抑制推迟到数字化之后。 然后使用线性相位数字滤波来抑制FM载波及其各自的边带的谐波，并且响应于该数字滤波提供的折叠频谱亮度信号被展开以将其恢复到其原始的全带宽。 该过程允许低于折叠载波频率的组延迟特性保持恒定，从而避免相位误差，这将干扰折叠信号到原始全带宽的展开。

公开(公告)号：US5257109A

公开(公告)日：1993-10-26

申请号：US721349

申请日：1991-06-28

申请人： Tokuichi Minakawa

发明人： Tokuichi Minakawa

IPC分类号： H04N5/911 ,  H04N5/922 ,  H04N5/923 ,  H04N9/79 ,  H04N9/793 ,  H04N9/83

CPC分类号： H04N9/7908 ,  H04N5/911 ,  H04N5/923 ,  H04N9/7933 ,  H04N9/83

摘要： A magnetic recording/reproducing apparatus, which includes: a reproduced level detector for detecting the level of a reproduced signal and a memory for storing the reproduced level detected by the detector; and when recording a video signal, the signal is recorded and reproduced in advance, and this reproduced level is stored in the memory, so that an amount of emphasis of a detail emphasis circuit in a reproducing system and an amount of equalization of an FM equalizer in the recording system can be controlled in accordance with the stored reproduced level; while when reproducing the video signal, the level of a reproduced FM luminance signal is detected by the reproduced level detector, so that an amount of equalization of an FM equalizer, an amount of cancellation of a line noise canceler, and an amount of cancellation of a noise canceler in a reproducing system can respectively be controlled in accordance with the detected reproduced level; whereby the characteristic of a video tape can be controlled in accordance with the type thereof on an apparatus-wide and integrated basis.

公开(公告)号：US5208707A

公开(公告)日：1993-05-04

申请号：US737685

申请日：1991-07-30

申请人： Yong-je Kim

发明人： Yong-je Kim

IPC分类号： G11B20/02 ,  H04N5/922 ,  H04N5/926 ,  H04N5/931 ,  H04N9/797

CPC分类号： H04N5/9315 ,  H04N5/926 ,  H04N9/7976

摘要： Disclosed is a circuit for maintaining compatibility between different image signal recording/reproducing systems. An adaptive de-emphasis unit is attached to the output of the folding frequency information detector of an improved circuit for maintaining compatibility between image signal recording/reproducing systems, in order to restore the signal adaptively emphasized by the adaptive emphasis unit during recording as stated above, to the original signal to prevent degradation in image quality. The adaptive de-emphasis unit comprises a soft switch, a horizontal high-pass filter, a horizontal low-pass filter, a level detector and a lookup table.

摘要翻译： 公开了一种用于维持不同图像信号记录/再现系统之间的兼容性的电路。 自适应去加重单元附加到用于维持图像信号记录/再现系统之间的兼容性的改进电路的折叠频率信息检测器的输出，以便如上所述在记录期间恢复自适应强调单元自适应强调的信号 ，以原始信号防止图像质量下降。 自适应去加重单元包括软开关，水平高通滤波器，水平低通滤波器，电平检测器和查找表。

公开(公告)号：US5191433A

公开(公告)日：1993-03-02

申请号：US497599

申请日：1990-03-23

申请人： Masahiro Honjo

发明人： Masahiro Honjo

IPC分类号： H04N5/922 ,  G11B20/06 ,  H04N5/92

CPC分类号： H04N5/9201 ,  H04N5/9203

摘要： A video tape recorder wherein when a video signal is frequency-modulated, the phase of a frequency-modulated wave is in a predetermined phase relationship with respect to the video signal. The frequency modulator is driven so that the video signal is time-base compressed to form a space of time. Then, a non-video signal is inserted into the space of time, and the frequency-modulated wave is brought into a predetermined phase having a synchronous relationship with the video signal. Furthermore, in another arrangement, during the reproducing operation, a regenerative demodulated signal is time-base expanded in order to avoid outputting noise due to the discontinuity in phase of the frequency-modulated wave which has arisen within the non-video signal contained space of the regenerated demodulated signal.

摘要翻译： 一种录像机，其中当视频信号被频率调制时，调频波的相位相对于视频信号处于预定的相位关系。 驱动频率调制器使得视频信号被时基压缩以形成时间空间。 然后，将非视频信号插入到时间空间中，并且调频波进入与视频信号具有同步关系的预定相位。 此外，在另一种布置中，在再现操作期间，再生解调信号被时基扩展，以避免由于在非视频信号包含的空间内产生的调频波的相位不连续而输出噪声 再生的解调信号。

公开(公告)号：US5189565A

公开(公告)日：1993-02-23

申请号：US553390

申请日：1990-07-17

申请人： Ichitaro Sato

发明人： Ichitaro Sato

IPC分类号： H04N5/922 ,  G11B20/02 ,  H04N5/923 ,  H04N5/931

CPC分类号： H04N5/9315 ,  H04N5/923

摘要： A slew rate converter is provided in a video signal recording circuit for limiting a signal having a high frequency and a high amplitude so as to avoid an over-modulation when the signal is reproduced. The high frequency and high amplitude component exceeding a pre-determined amplitude is detected and applied to the slew rate converter for reducing its slew rate so that the signal component having the high frequency and high amplitude is suppressed.

摘要翻译： 在视频信号记录电路中提供了一个转换速率转换器，用于限制具有高频和高振幅的信号，以避免信号再现时的过调制。 检测到超过预定幅度的高频和高振幅分量并将其施加到转换速率转换器以降低其转换速率，从而抑制具有高频和高振幅的信号分量。

公开(公告)号：US5185679A

公开(公告)日：1993-02-09

申请号：US350252

申请日：1989-05-11

申请人： Hidetoshi Mishima ,  Keiji Hatanaka

发明人： Hidetoshi Mishima ,  Keiji Hatanaka

IPC分类号： H04N5/922 ,  G11B20/06 ,  G11B20/22 ,  H04N5/93

CPC分类号： H04N5/93

摘要： An FM signal which is partly missing zero crossing points is supplied to an input terminal, to which a second polarity discriminating circuit and a lower side band suppressing circuit followed by a first polarity discriminating circuit are coupled together. A pulse extracting circuit receives the outputs of the first polarity discriminating circuit and a second polarity discriminating circuit to produce pulses corresponding only to portions of the FM signal at which the zero crossing points are absent. The pulses thus obtained are subsequently combined in a waveform reforming circuits with the FM signal from the input terminal, thereby permitting the FM signal to regain the zero crossing points.

摘要翻译： 部分缺少过零点的FM信号被提供给输入端子，第二极性鉴别电路和下边带抑制电路跟随第一极性鉴别电路耦合到该输入端子。 脉冲提取电路接收第一极性判别电路的输出和第二极性鉴别电路，以产生仅对应于不存在过零点的FM信号的部分的脉冲。 这样获得的脉冲随后在波形重整电路中与来自输入端的FM信号组合，从而允许FM信号重新获得过零点。

公开(公告)号：US5173812A

公开(公告)日：1992-12-22

申请号：US688633

申请日：1991-04-19

申请人： Gerd Reime

发明人： Gerd Reime

IPC分类号： H04N5/7826 ,  G11B27/029 ,  H04N5/91 ,  H04N5/922

CPC分类号： H04N5/91 ,  G11B27/029

摘要： A video recorder having recording/reproducing apparatus for subsequent recording of data signals in defined video lines of a previously recorded signal existing on a magnetic tape. The recording/reproducing apparatus (10, 11, 12, 19, 20) records FM signals onto the magnetic tape and reads previously recorded FM signals from the magnetic tape. A voltage controlled oscillator VCO (13) is connected between a data signal input terminal (16) and a recording terminal (11), for converting data signals routed to the data input terminal (16) into FM data signals. A switch (14) is connected between the recording terminal (11) and a VCO (13) output, for switching the recording terminal (11) to the VCO (13) output for the duration of the recording mode of the data recording apparatus. A circuit (17) detects a line sync signal (22) of the video lines passing through the data recording apparatus, for switching the recording/reproducing apparatus from recording mode to reproducing mode immediately before the end of a video line, and for switching from the reproducing mode to the recording mode immediately after detection of the line sync signal (22). A phase comparator circuit (23) has phase comparator inputs, one connected to the VCO (13) output and another to the reproducing output (12), for generating a phase deviation signal for the VCO (13) input and for setting an in-phase oscillation of the VCO (13) with the oscillation picked up by the phase comparator circuit (23). A data signal switch (18) has the VCO (13) input connected either to the output of the phase comparator circuit (23), or to the data signal recording apparatus input terminal (16) for the duration of the recording mode of the data signal recording apparatus.

摘要翻译： 一种具有记录/再现装置的录像机，用于随后在存在于磁带上的先前记录的信号的定义视频行中记录数据信号。 记录/再现装置（10,11,12,19,20）将FM信号记录到磁带上并从磁带读取先前记录的FM信号。 压控振荡器VCO（13）连接在数据信号输入端（16）和记录端（11）之间，用于将路由至数据输入端（16）的数据信号转换为FM数据信号。 开关（14）连接在记录终端（11）和VCO（13）输出端之间，用于在数据记录装置的记录模式期间将记录终端（11）切换到VCO（13）输出。 电路（17）检测通过数据记录装置的视频线的行同步信号（22），用于将记录/再现装置从紧接在视频行结束之前的记录模式切换到再现模式，并从 在线检测到同步信号（22）之后立即将再现模式转换为记录模式。 相位比较器电路（23）具有相位比较器输入，一个连接到VCO（13）输出，另一个连接到再现输出（12），用于产生用于VCO（13）输入的相位偏差信号， 由相位比较电路（23）拾取的振荡使VCO（13）的相位振荡。 数据信号开关（18）的VCO（13）输入端连接到相位比较器电路（23）的输出，或数据信号记录装置输入端（16），持续数据记录模式 信号记录装置。

公开(公告)号：US5144435A

公开(公告)日：1992-09-01

申请号：US532526

申请日：1990-06-01

申请人： Scott C. Knauer ,  Arun N. Netravali

发明人： Scott C. Knauer ,  Arun N. Netravali

IPC分类号： H04B1/10 ,  H04N5/21 ,  H04N5/922 ,  H04N7/015 ,  H04N7/08 ,  H04N7/16 ,  H04N7/26 ,  H04N11/08 ,  H04N11/24 ,  H04N19/00

CPC分类号： H04N21/2383 ,  H04N21/4382 ,  H04N5/21 ,  H04N7/0803 ,  H04N7/166

摘要： An arrangement for a television receiver to attenuate correlated noise injected by the transmission medium. Recognizing that there is substantial line to line correlation of the transmission noise injected by interfering television stations, this arrangement enhances noise immunity by inserting in the receiver a de-emphasis stage that includes a circuit for removing the correlated noise. To account for the modifications to the desired signal that are introduced by the de-emphasis circuit, a pre-emphasis circuit is included in the transmitter. In accordance with one embodiment, the receiver's circuit comprises a feed-forward arrangement where the received signal of a scan line is subtracted from a fraction of the received signal of the previous scan line. At the transmitter, a feedback loop develop a scan line to be transmitted that corresponds to a video scan line subtracted from a fraction of the previous scan line to be transmitted. This arrangement also removes some of the correlation in the signal of the video scan lines, which results in the developed scan lines having lower amplitudes. The latter permits insertion of a gain stage, which increases the signal power relative to the noise and thereby improves the signal to noise ratio at the receiver.

摘要翻译： 一种用于电视接收机衰减由传输介质注入的相关噪声的装置。 认识到由干扰电视台注入的传输噪声存在大量的线路相关性，这种布置通过在接收机中插入包括用于去除相关噪声的电路的去加重阶段来增强抗噪声能力。 为了解决由去加重电路引入的期望信号的修改，预加重电路包括在发送器中。 根据一个实施例，接收机的电路包括前馈装置，其中扫描线的接收信号从先前扫描线的接收信号的一部分中减去。 在发射机处，反馈环路产生要发射的扫描线，该扫描线对应于从要发送的先前扫描线的一小部分中减去的视频扫描线。 这种布置还消除了视频扫描线的信号中的一些相关性，这导致显影的扫描线具有较低的振幅。 后者允许插入增益级，其增加相对于噪声的信号功率，从而提高接收机处的信噪比。

公开(公告)号：US5136392A

公开(公告)日：1992-08-04

申请号：US443461

申请日：1989-11-30

申请人： Shigeru Ganse

发明人： Shigeru Ganse

IPC分类号： G11B20/06 ,  H04N5/911 ,  H04N5/922 ,  H04N5/931 ,  H04N9/87

CPC分类号： H04N5/931 ,  H04N5/911 ,  H04N9/87

摘要： In a video reproducing apparatus having a head for reproducing a recorded frequency modulated signal and a frequency demodulator for demodulating the reproduced signal output from the head, a circuit interposed between the head and frequency demodulator comprises an adder having an input receiving the reproduced frequency modulated signal output from the head, a limiter connected between the output of the adder and the frequency demodulator for providing an amplitude limited output to the latter, and a feedback loop for also applying the amplitude limited output from the limiter to a second input of the adder so as to prevent occurrence of a reversing phenomenon and of an abnormal noise bar output, and thereby improve the reproduced picture quality.