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公开(公告)号：US4017677A
公开(公告)日：1977-04-12
申请号：US590484
申请日：1975-06-26
申请人： Alfred Lynn Baker
发明人： Alfred Lynn Baker
CPC分类号： G11B23/0007 , H04N5/7605 , H04N5/903 , H04N5/91 , H04N9/882
摘要： In a video disc player, a first FM signal recovered from the disc is subject to frequency demodulation to obtain a composite color video signal, and a second FM signal recovered from the disc is also demodulated to obtain an accompanying sound signal. The player includes a defect detector, monitoring the first FM signal to identify carrier frequency departures from the intended deviation range, and switching apparatus for effecting a substitution of stored video signals, in replacement of the output of the video FM detector, when the defect detector identifies such departures. A squelch control signal generator is rendered responsive to an output of the defect detector, and develops a squelch signal when the defect indication persists beyond a predetermined minimum length of time. The squelch signal is employed to inhibit the passage of sound and video signals to player output terminals. The squelch control signal generator is additionally rendered responsive to player apparatus controlling placement of the player stylus in and out of playback position (e.g., controlling lowering/lifting of stylus arm), so that removal of stylus from playback position initiates squelch signal development without need for passage of said predetermined minimum length of time.
摘要翻译： 在视盘播放机中，从盘恢复的第一FM信号进行频率解调以获得复合彩色视频信号，并且从盘恢复的第二FM信号也被解调以获得伴音信号。 播放器包括缺陷检测器，监视第一FM信号以识别与预期偏差范围的载波频率偏差;以及切换装置，用于替换存储的视频信号，以替代视频FM检测器的输出，当缺陷检测器 识别出发。 响应于缺陷检测器的输出而产生静噪控制信号发生器，并且当缺陷指示持续超过预定的最小时间长度时，产生静噪信号。 静噪信号用于抑制声音和视频信号通过播放器输出端。 静音控制信号发生器还响应于播放器设备控制播放器触笔进出播放位置（例如，控制触针的下降/提升）的位置，使得从重放位置移除触笔启动静噪信号发展而不需要 用于通过所述预定的最小时间长度。
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公开(公告)号：US4086617A
公开(公告)日：1978-04-25
申请号：US756833
申请日：1977-01-05
申请人： Alfred Lynn Baker
发明人： Alfred Lynn Baker
CPC分类号： G11B19/20 , G11B19/02 , G11B3/08529
摘要： Coupling of pickup arm housing to a slow moving belt for translational motion during record playback is controlled by a play solenoid, while coupling to a fast moving belt for fast forward and reverse motions is controlled by respective forward and reverse solenoids. Player includes manually actuated push button controls for play, forward search, reverse search, pause, reject and power on/off functions. Mechanism actuated switches include a land switch actuated when pickup location is over beginning of recorded information, a travel limit switch actuated when pickup location is beyond ending of recorded information, and a rest switch placed in one switching condition when housing returns to an off-record rest position.
摘要翻译： 拾音臂壳体与记录播放期间平移运动的缓慢移动带的耦合由播放电磁线圈控制，同时耦合到快速移动的皮带以进行快进和反向运动，由各自的正向和反向螺线管控制。 播放器包括用于播放，前向搜索，反向搜索，暂停，拒绝和开机/关机功能的手动启动按钮控件。 机构致动开关包括当拾取位置超过记录信息的开始时启动的平台开关，当拾取位置超出记录信息结束时致动的行程限位开关，以及当壳体返回到断开记录时处于一个切换状态的休息开关 休息位置。
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公开(公告)号：US4017678A
公开(公告)日：1977-04-12
申请号：US590483
申请日：1975-06-26
申请人： Alfred Lynn Baker
发明人： Alfred Lynn Baker
CPC分类号： G11B19/02
摘要： Video disc player pickup circuit recovers picture information in the form of carrier waves, the instantaneous frequency of which varies over a given deviation range in accordance with the amplitude of composite color video signals, in the course of pickup tracking of successive convolutions of the disc record's groove. Succeeding the innermost groove convolution containing recorded picture information are a plurality of groove convolutions containing an end-of-recording signal comprising unmodulated carrier waves at a given instantaneous frequency within said deviation range. Signal processing circuitry of the video disc player includes a sync separator for separating a deflection synchronizing component from the composite color video signals recovered during playback of the groove convolutions containing picture information. Video disc player also includes a defect detector monitoring carrier frequency departures from the given deviation range, and a squelch signal generator responsive to the output of the defect detector. An end-of-play signal generator responds to the continuance for a given time interval of a simultaneous absence of outputs from sync separator and squelch signal generator by generating an end-of-play signal, which is utilized to terminate record playback efforts and to restore pickup apparatus to a rest position.
摘要翻译： 视频光盘播放器拾取电路以拾取跟踪盘记录的连续卷积的过程，以载波的形式恢复图像信息，载波的形式根据复合彩色视频信号的幅度在给定的偏差范围内变化。 槽。 成为包含记录图像信息的最内槽卷积是包含在所述偏差范围内的给定瞬时频率处包含未调制载波的记录结束信号的多个凹槽卷积。 视频光盘播放机的信号处理电路包括一个同步分离器，用于从包含图像信息的凹槽卷积的回放期间恢复的复合彩色视频信号中分离偏转同步分量。 视频盘播放器还包括检测载波频率偏离给定偏差范围的缺陷检测器，以及响应于缺陷检测器的输出的静噪信号发生器。 播放终止信号发生器响应来自同步分离器和静噪信号发生器的同时没有输出的给定时间间隔的连续性，通过产生用于终止记录播放工作的终止播放信号，并且 将拾取装置恢复到静止位置。
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公开(公告)号：US4057826A
公开(公告)日：1977-11-08
申请号：US590485
申请日：1975-06-26
申请人： Alfred Lynn Baker
发明人： Alfred Lynn Baker
CPC分类号： H04N9/87
摘要： Video disc player is provided with a sync separator which is responsive to output of luminance comb filter after de-emphasis circuit processing. Input to comb filter circuitry is provided by amplitude modulator, responsive to carrier wave oscillations from a voltage controlled oscillator (VCO) and to composite video signals provided by a defect compensation system. The compensation system normally supplies an output directly derived from the player's pickup circuits, but, under defect conditions, substitutes stored video signals. The VCO is a component of a phase locked loop (PLL) arrangement, also including a burst gate for selectively passing color synchronizing information contained in the modulator output. Gating pulses for the burst gate are generated by apparatus responsive to the sync separator output, the generating apparatus including a capacitor charging circuit activated by the trailing edge of a separator output pulse to control gating pulse termination, and a separate capacitor discharging circuit activated by the trailing edge of a separator output pulse to control gating pulse initiation. Also responsive to an output of the sync separator is a keying pulse generator for controlling keyed clamping of the luminance comb filter output, with keying pulse timing determined by differentiated and integrated versions of the separator output.
摘要翻译： 视频光盘播放器设置有同步分离器，该同步分离器响应于去加重电路处理之后的亮度梳状滤波器的输出。 梳状滤波器电路的输入由幅度调制器提供，响应于来自压控振荡器（VCO）的载波振荡以及由缺陷补偿系统提供的复合视频信号。 补偿系统通常提供直接来自播放器拾取电路的输出，但在缺陷条件下，替代存储的视频信号。 VCO是锁相环（PLL）装置的组件，还包括用于选择性地通过调制器输出中包含的彩色同步信息的脉冲串门控。 用于突发门的门控脉冲由响应于同步分离器输出的装置产生，该发生装置包括由分离器输出脉冲的后沿激活以控制门控脉冲终止的电容器充电电路以及由该分配器输出激活的单独的电容器放电电路 分离器输出脉冲的后沿来控制门控脉冲启动。 响应于同步分离器的输出也是用于控制亮度梳状滤波器输出的键控钳位的键控脉冲发生器，其中键控脉冲定时由分离器输出的差分和集成版本确定。
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公开(公告)号：US4038686A
公开(公告)日：1977-07-26
申请号：US664674
申请日：1976-03-08
申请人： Alfred Lynn Baker
发明人： Alfred Lynn Baker
IPC分类号： H03M5/12 , G11B9/06 , G11B20/06 , H03K9/06 , H04B1/10 , H04L25/49 , H04N5/94 , H04N9/882 , H04N5/76
CPC分类号： H04N9/882
摘要： In a video disc player, color picture information recorded in FM carrier form is recovered from the output of player's signal pickup apparatus by an FM demodulator. The FM demodulator includes zero crossing detector circuitry providing a pulse in response to each zero crossing of its signal input, a monostable multivibrator developing a pulse of a substantially fixed width when triggered by an output pulse of the zero crossing detector, and means for low pass filtering the output of the monostable multivibrator to develop signals for application to the player's video signal processing circuits. An output pulse of the zero crossing detector, and an output pulse of the monostable multivibrator subject to a selected delay comprise the inputs to a gate circuit, which develops an output pulse upon any instance of overlapping presence of the respective input pulses to indicate the presence of input signal conditions tending to produce a "white" defect during picture display. A capacitor is subject to charging toward the turn-on threshold potential of a second gate having its inputs coupled thereto. Resetting of the capacitor charging circuit is effected in response to an output of the monostable multivibrator. The capacitor charging time constant is selected so that the threshold is reached if the recurrence rate of the multivibrator output pulses falls below a reference rate less than twice the lowest intended picture carrier frequency, whereby gate switching indicates the presence of input signal conditions tending to produce a "black" defect during picture display. The respective defect indications are subject to summing and stretching, and are utilized to control substitution of stored picture information during defect occurrences.The present invention relates to novel defect compensation apparatus suitable for use in playback of a video record employing an FM carrier recording format, and to novel defect detection apparatus for use in effecting such defect compensation.In U.S. Pat. No. 3,842,194, issued to Jon K. Clemens on Oct. 15, 1974 a video disc recording/playback system is disclosed in which recorded information appears in the form of geometric variations in the bottom of a spiral groove in the surface of a disc substrate covered by a conductive coating, with a dielectric layer overlying the conductive coating. A playback stylus, including a conductive electrode affixed to an insulating support, is received in the record groove. The stylus electrode cooperates with the disc coatings to form a capacitance which varies, as the disc is rotated, in accordance with the groove bottom geometry variations passing beneath the stylus electrode. Appropriate circuitry coupled to the stylus electrode translates the capacitance variations to electrical signal variations representative of the recorded information.In a desirable form of the above-described capacitive video disc system, the recorded information comprises a carrier frequency modulated in accordance with video signals and appears in the form of successive groove bottom depth alternations between maximum and minimum depths. In use of such a FM carrier recording format, FM detector apparatus must be employed in the player to obtain video signals from the recovered FM signal.Illustratively, the FM detector in the player may comprise a zero-crossing detector and a monostable multivibrator responsive thereto for providing an output pulse of a standard width and amplitude in response to each zero-crossing of the input signal. The output pulses are applied to a low-pass filter having a passband substantially matching the recorded video signal bandwidth to develop the desired video signals.In operation of a video disc player of the above-described type to recover recorded video signals for image display purposes, a problem observable in the displayed picture (in the absence of suitable compensation) is the intermittent appearance in random locations of disturbances in the form of white and/or black spots and streaks supplanting the appropriate picture information. These picture defects may vary in length, thickness and persistence of appearance. While not destructive of the picture information as a whole, the intermittent appearance of such picture defects can be a source of considerable annoyance to the viewer. The present invention is concerned with compensation apparatus for substantially eliminating or significantly reducing the annoying effects of such picture defects.As explained in the copending application, Ser. No. 594,429 of Jon K. Clemens, et al., now U.S. Pat. No. 4,001,496, a variety of different causes may lead to the production of different ones of the annoying picture spots and streaks. Some of the causes may be associated with defects in the record itself, which may originate in various stages associated with the record production. Other causes may be associated with the condition encountered in a particular playing of a given disc: e.g., due to stylus encounters with debris of various forms in various regions of the disc groove, which may be subject to change with successive plays of a disc. Other causes may be associated with the past history of use or abuse of the disc being played, and involve mechanical alterations of the disc surface: e.g., scratches, chips or dents; or chemical alterations of the disc surface, due for example, to the effects of fingerprints on the disc coatings. Thus, there are myriad causes of differing types which result in the defect problem having a high degree of unpredictability, and varying from disc to disc, play to play, groove region to groove region, etc.In the aforementioned copending Clemens, et al. application, it is recognized that the defects are manifested as spurious alterations of the repetition rate of zero crossings (e.g., introducing extra zero crossings, or missing zero crossings) in the recovered signal. The result of extra zero crossings or missing zero crossings appears as an abrupt change in frequency toward and usually beyond one of the deviation range frequency limits associated with the recorded signal. This appears in the video output signal of the FM detector filter as a shift to an extreme white or black level. Moreover, due to the limited frequency response of the filter, the spurious shift (and subsequent return to normal) is stretched in time relative to the actual duration of the spurious condition in the input FM signal. Additionally, ringing effects associated with reactive elements of the filter are likely to persist in disturbing the output video signal for at least a short period following termination of the spurious input signal condition.The aforesaid copending Clemens, et al. application employs an approach to defect detection which is based upon several well-grounded premises: (1) that the instantaneous carrier frequency of the FM signal input to the player's FM detector is shifted by desired signal information only within known, fixed limits (i.e., as determined by the deviation range employed in recording), wherefore shifts to frequencies beyond such limits are due not to desired signal information but to spurious, defective signal development or delivery conditions; (2) that essentially all of the noticeable, troublesome picture defects of the type here discussed stem from input signal defects that shift the apparent instantaneous carrier frequency well beyond the known deviation range limits.In the approach of the Clemens, et al. application, a first means coupled to the player's FM demodulator develops an output impulse when the instantaneous frequency of the recovered signal exceeds a first threshold frequency beyond the upper limit of the intended deviation range; additional means coupled to the FM demodulator develops an output impulse when the instantaneous frequency of the recovered signal falls below a second threshold frequency beneath the lower limit of the intended deviation range. The respective output impulses are summed in an adder to form a defect indication signal, providing an indication of the intervals occupied by those input signal defects that engender the troublesome picture defects previously discussed. The defect indication signal is used to control switching of the player from a normal operating mode to a defect compensation mode. In the latter mode, a delayed signal constituting information from a preceding image line is used, in substitution for the current video signal output of the FM detector, to develop the player output signal. Because of the general redundancy of information in successive image lines, the preceding line information substitution serves to mask the defect occurrence, rendering it relatively unnoticeable to the image viewer. However, because of the limited bandwidth of the video signal output filter of the player's FM demodulator, the termination of the signal disturbance in the output of the latter filter may be expected to lag the termination of the associated input signal defect. In recognition of this lag effect, there is associated with the player mode switching apparatus of the aforesaid Clemens, et al. application suitable means for effectively "stretching" the effect of the defect indication pulses so as to maintain the substitution mode until the current signal output of the FM detector filter is substantially free of the disturbances that cause defective image display.The present invention is directed to improved forms of defect compensation apparatus of the general type of the Clemens, et. al. application as described above.A technique for identification of input signal frequency departures from the above-mentioned threshold frequency boundaries, as disclosed in the Clemens, et al. application, relies upon comparison of the instantaneous level of a video signal developed from an output of the player's FM detector with maximum and minimum levels closely related to the instantaneous video signal levels that are produced by that FM detector in response to input signal frequencies at the deviation range limits. The input to the level comparators is not the normally filtered video signal output of the FM detector used for image display purposes, but rather is an output developed by a defect detector input filter in the form of a low pass filter having a cutoff frequency well above the highest recorded video signal frequency. For accuracy of the level comparison, the input to the level comparators appropriately includes the DC component of the recovered video signal.A rise in the voltage level at the output of the defect detector input filter to a level above a high level comparator threshold, initiates a defect indication pulse in the comparator output; in a representative FM format wherein video signal excursions in the "white" direction cause an increase in carrier frequency, this comparator output is indicative of the onset of a "white" defect in the displayed image. A similar development of a "black" defect indication pulse is provided by a low level comparator in response to a shift to the defect detector filter output level below the low level comparator threshold. The wideband response of the defect detector input filter aids in the provision of an early indication of the onset of the defect by the level comparators.In accordance with the principles of the present invention, detection of input signal frequency shifts above an upper threshold frequency value is effected by a timing-responsive technique that possesses advantages in practical implementation over the above-described voltage level comparison techniques. By judicious use of a pair of signals already available in the circuitry of a suitable form of FM detector, a timing comparison of such signals may be effected in a manner permitting white defect detection with relatively simple and reliable apparatus.In accordance with an illustrative embodiment of the present invention, for use with an FM detector of the previously described type employing a monostable multivibrator triggered by the output pulses of a zero crossing detector, an output of the multivibrator is subjected to a short delay of a magnitude selected to ensure that the leading edge of the delayed pulse trails the trailing edge of the crossing detector pulse which triggered the development of that multivibrator pulse. Coincidence in timing between an output pulse of the zero crossing detector and any segment of the delayed multivibrator pulse is detected as a white defect indication by appropriate logic circuitry. The multivibrator output pulse width is selected so that the sum of such pulse width, and the amount by which the delayed multivibrator pulse lags the zero crossing pulse by which it was triggered, corresponds to a period at twice the desired upper threshold frequency.Use of the aforesaid timing responsive apparatus enables accurate white defect detection without the need for response to a DC component of a filtered signal (present in use of the previously mentioned voltage level comparison technique), whereby DC stability requirements are eased for the defect detection apparatus.A further advantage of the described timing responsive apparatus resides in the fact that its ability to discriminate between white defects and desired white signal components is essentially independent of the defect duration. In contrast, the need for an integrating filter in the voltage level comparison apparatus renders its ability to distinguish between defects and desired signal components proportional to defect duration. A practical setting for the high level comparator threshold voltage (allowing for time base errors and harmonic distortions of desired signal components and circuit instabilities, so as to avoid unnecessary triggering into the defect compensation mode) may fall at a level not reached by the output of the defect detector filter in response to short white defect conditions. This can be troublesome, since it is observed that, in the described video disc player environment, a relatively large percentage of white defect occurrences are of quite short duration, with many corresponding to a single "extra" zero crossing, or to a single "misplaced" zero crossing.A white defect detector of the herein described timing responsive type may be satisfactorily associated with a black defect detector of the voltage level comparator type in a defect compensation system which sums the outputs of the respective defect detectors, suitably "stretches" the output of the summing device, and controls player switching between normal and substitution modes in accordance with the stretched output. However, in accordance with preferred forms of the present invention, the associated black defect detector is desirably also of a timing responsive type.In accordance with an illustrated embodiment of such preferred forms of the invention, the associated black defect detector incorporates an RC capacitor charging circuit which is reset by each output pulse of the FM detector's monostable multivibrator. The RC time constant of the charging circuit is selected so that the capacitor potential reaches the threshold potential of a black defect indicating device if the time between successive zero crossing of the FM detector input signal exceeds a period at twice the desired lower threshold frequency.Use of black defect detection apparatus of the above-described timing responsive form permits early recognition of the onset of a black defect, without conflict with the setting of a threshold precluding false triggering of defect compensation during desired black signal component appearances. In contrast, in use of voltage level comparison approach for black defect detection, such a conflict arises in the selection of a cutoff frequency for the defect detector input filter. Setting of a high cutoff frequency, to facilitate rapid recognition of the onset of a black defect, enhances the possibility of false triggering because of insufficient attenuation of the double carrier frequency component of the zero crossing detector output. Reduction of the cutoff frequency to alleviate the false triggering problem compromises the speed and surety of recognition of black defects.In embodiments of the present invention using the timing responsive approach for both black and white defect detection, a simplification of the filter circuitry for the associated FM demodulator may be realized relative to that required for the aforementioned voltage level comparison approach.
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