公开(公告)号：US5493209A

公开(公告)日：1996-02-20

申请号：US140343

申请日：1993-10-20

申请人： Linley F. Gumm ,  Dana E. Whitlow

发明人： Linley F. Gumm ,  Dana E. Whitlow

IPC分类号： G01R23/16 ,  G01R23/173 ,  H03D7/16 ,  H03J7/32 ,  H04N7/10 ,  H04N17/00 ,  H04N7/04

CPC分类号： H03D7/163 ,  H03J7/32 ,  H04N17/00 ,  H04N7/102 ,  G01R23/16

摘要： A spectrum analyzer (50) has a tunable trigger acquisition system (52) that includes a selectable trigger acquisition bandwidth. Sufficiently wide signal acquisition bandwidth is obtained by tapping into a high-frequency IF amplifier (54) signal and down-converting it to a moderate IF frequency for trigger extraction. A down-conversion local oscillator (62) is phase-lock-loop (64) tunable over a range of the high IF frequencies to allow extracting a time and frequency selectable trigger from the desired carrier signal frequency even if the spectrum analyzer is substantially offset in frequency from the desired carrier. The moderate frequency IF amplifier (66) includes a switchable bandpass filter (68) that provides adequate selectivity to detect triggers from a variety of signal types while rejecting unwanted signals such as adjacent channel CATV carriers that are often detectable when the measurement frequency is offset toward the channel edges.

摘要翻译： 频谱分析器（50）具有包括可选择的触发采集带宽的可调谐触发采集系统（52）。 通过点击高频IF放大器（54）信号并将其下变频到中频IF频率进行触发提取，可获得足够宽的信号采集带宽。 降频转换本地振荡器（62）是在高IF频率的范围上可调谐的相位锁定环（64），以允许从所需载波信号频率提取时间和频率可选择的触发，即使频谱分析仪基本上被偏移 频率从所需载波。 中频IF放大器（66）包括可切换带通滤波器（68），其提供足够的选择性来检测来自各种信号类型的触发，同时排除诸如邻近信道CATV载波之类的不需要的信号，当测量频率向 通道边缘。

公开(公告)号：US06246717B1

公开(公告)日：2001-06-12

申请号：US09185418

申请日：1998-11-03

申请人： Xiaofen Chen ,  Linley F. Gumm ,  Dana E. Whitlow ,  Larry R. Lockwood

发明人： Xiaofen Chen ,  Linley F. Gumm ,  Dana E. Whitlow ,  Larry R. Lockwood

IPC分类号： H04Q120

CPC分类号： H04B3/46 ,  H04L1/205

摘要： A system and method for in-service transmitter phase noise measurements determines phase nonlinearity by way of comparing unfiltered signal samples and regenerated reference signal samples to calculate phase nonlinearity error. Linear distortion is removed from the received signal samples in order to truly characterize nonlinear behavior of the transmitter. The unfiltered signal samples are generated without applying the receiver shaping filtering. Reference signal samples are regenerated from estimated transmitted symbols derived from the unfiltered signal samples. The transmitted symbols are estimated using a segmented slicer which dynamically estimates constellation decision levels from the unfiltered signal samples. A weighted, least-square based polynomial regression is performed on phase error samples of the unfiltered signal samples to estimate a phase nonlinear error function while suppressing the impact of other non-systematic distortions. The nonlinear phase error is removed from the phase error to produce phase noise containing carrier phase jitter and additive noise. A threshold is determined for replacing phase error values outside the threshold with random values having a distribution equivalent to the carrier phase jitter. The carrier phase jitter may be displayed as a power spectrum of the phase noise.

摘要翻译： 用于在线发射机相位噪声测量的系统和方法通过比较未滤波的信号样本和再生参考信号样本来确定相位非线性，以计算相位非线性误差。 从接收的信号采样中去除线性失真，以便真实地表征发射机的非线性特性。 在不应用接收机整形滤波的情况下生成未滤波的信号样本。 参考信号样本从未滤波的信号样本导出的估计的传输符号中再生。 使用分段限幅器来估计所发送的符号，其从未滤波的信号样本中动态地估计星座决定级别。 对未滤波信号样本的相位误差样本进行加权最小二乘回归，以估计相位非线性误差函数，同时抑制其他非系统失真的影响。 从相位误差去除非线性相位误差，产生包含载波相位抖动和加性噪声的相位噪声。 确定阈值以用具有等于载波相位抖动的分布的随机值来替换阈值之外的相位误差值。 载波相位抖动可以显示为相位噪声的功率谱。

公开(公告)号：US5617137A

公开(公告)日：1997-04-01

申请号：US452782

申请日：1995-05-30

申请人： Dana E. Whitlow

发明人： Dana E. Whitlow

IPC分类号： H04N17/00 ,  H04N17/02

CPC分类号： H04N17/00

摘要： An in-service composite triple beats (CTB) measurement system for a cable television (CATV) system isolates and measures weak composite triple beat components in the presence of a visual carrier modulated with program material for selected channels of the CATV system. Each channel is demodulated and digitized in a frequency bandwidth about the visual carrier for the channel (the CTB frequency range). The digitized video is sampled during the vertical interval, and corresponding samples from consecutive frames are differenced, squared and accumulated to produce a CTB value, which may be scaled and corrected for noise. Noise correction is achieved by performing the same measurement, but digitizing in a frequency bandwidth offset from the CTB frequency range. The difference between the two measurements provides a corrected CTB value. For further accuracy the automatic gain control of the demodulator may be enabled only during the vertical interval, and the frequency control of a phase locked loop that produces the clock for the digitization of the video signal may be turned off during the vertical interval. Finally the amplitude of the sync tips of the demodulated video signal may be minimized prior to digitization.

摘要翻译： 用于有线电视（CATV）系统的在线复合三重（CTB）测量系统在有CATV系统的选定频道的程序资料调制的视觉载体的存在下隔离和测量弱复合三重拍摄组件。 每个通道在关于通道的可视载波（CTB频率范围）的频率带宽中进行解调和数字化。 数字化视频在垂直间隔期间被采样，并且来自连续帧的对应样本被差分，平方和累积，以产生CTB值，其可以被缩放并校正噪声。 通过执行相同的测量来实现噪声校正，但是在从CTB频率范围偏移的频带中数字化。 两个测量值之间的差异提供了校正的CTB值。 为了进一步的精确度，解调器的自动增益控制可以仅在垂直间隔期间启动，并且在垂直间隔期间可以关闭产生用于数字化视频信号的时钟的锁相环的频率控制。 最后，解调后的视频信号的同步提示的幅度可以在数字化之前被最小化。

公开(公告)号：US4917463A

公开(公告)日：1990-04-17

申请号：US46806

申请日：1987-05-05

申请人： Thomas S. Buzak ,  Rolf S. Vatne ,  Dana E. Whitlow

发明人： Thomas S. Buzak ,  Rolf S. Vatne ,  Dana E. Whitlow

IPC分类号： G02F1/133 ,  G02F1/1333

CPC分类号： G02F1/133348

摘要： A liquid crystal light valve (10) includes compensation for wire shadow effects caused by the interception of writing beam primary electrons as they propagate through the collector electrode (66). The wire shadows stem from the lack of charge deposited on target surface regions ( 106) intended to be addressed by the writing electron beam (60a). The present invention applies to the collector electrode an appropriate voltage that diverts the paths (112) of nonintercepted writing beam electrons toward target surface regions directly below the collector electrode portions that intercepted the writing beam electrons. Diverting the paths of nonintercepted electrons provides a more uniform charge distribution on the target surface (45) and thereby fills the charge voids created by the electron intercepting portions of the collector electrode.

摘要翻译： 一种液晶光阀（10）包括补偿当一束电子束通过集电极（66）传播时截取写入束一次电子所引起的线阴影效应。 线阴影源于沉积在预期由写入电子束（60a）寻址的目标表面区域（106）上的电荷的缺乏。 本发明适用于集电极适当的电压，该电压将非接收的写入光束电子的路径（112）转移到截取写入光束电子的集电极部分正下方的目标表面区域。 转移非接受电子的路径在目标表面（45）上提供更均匀的电荷分布，从而填充由集电极的电子截取部分产生的电荷空隙。

公开(公告)号：US4791339A

公开(公告)日：1988-12-13

申请号：US46955

申请日：1987-05-05

申请人： Arthur J. Draz ,  Dana E. Whitlow ,  Stephen F. Blazo

发明人： Arthur J. Draz ,  Dana E. Whitlow ,  Stephen F. Blazo

IPC分类号： G02F1/13 ,  G02F1/133 ,  G02F1/1333 ,  H04N5/59 ,  H04N9/31 ,  H01J29/52 ,  H01J29/56

CPC分类号： G02F1/133348 ,  H04N5/59 ,  H04N9/3108

摘要： An electrical circuit compensates for spatial variations in the light transmittance of the target surface (45) of an electron beam-addressed liquid crystal light valve (10). Such variations in light transmittance, which stem in part from the position dependent angle of incidence of the writing beam electrons and position dependent alignment layer variations arising out of manufacturing process limitations, affect the ability to achieve a monotonic gray scale luminance over the display surface. The compensating circuit adjusts the amount of beam current of the writing electron beam by varying the gain and offset voltage of the video signal, which modulates the writing beam current. This is accomplished by applying the X and Y scan position signals to a correction signal generator (102), which produces gain correction and offset correction signals whose magnitudes vary in response to instantaneous scan position of the writing electron beam on the target surface of a particular light valve. The gain correction and offset correction signals alter the character of the video signal, which is then delivered to the Z-axis driver of the writing beam-producing cathode ray tube.

摘要翻译： 电路补偿电子束寻址液晶光阀（10）的目标表面（45）的透光率的空间变化。 透射率的这种变化部分地来自制造过程限制引起的书写光束电子的位置相关入射角和与位置相关的取向层变化的影响，影响在显示表面上实现单调灰度亮度的能力。 补偿电路通过改变调制写入光束电流的视频信号的增益和偏移电压来调节写入电子束的束电流量。 这通过将X和Y扫描位置信号施加到校正信号发生器（102）来实现，校正信号发生器（102）产生增益校正和偏移校正信号，其幅度随着写入电子束在特定的目标表面上的瞬时扫描位置而变化 光阀。 增益校正和偏移校正信号改变了视频信号的特性，然后传送给写入光束产生阴极射线管的Z轴驱动器。