公开(公告)号：US5001565A

公开(公告)日：1991-03-19

申请号：US530227

申请日：1990-05-30

申请人： Kenneth B. Freeman ,  Fred W. Caspari

发明人： Kenneth B. Freeman ,  Fred W. Caspari

IPC分类号： H04N5/217

CPC分类号： H04N5/217

摘要： A system and method of automatically deriving and using a black level control signal for use in long term target integrating camera systems is disclosed. The method employs the steps of, sequentially, first operating the camera in a long term target integration manner at a pre-selected exposure time and detecting and holding the inverse peak level of the television video signal derived from this scan taken from the central portion of the target, generating a corrective signal from the held inverse peak level and applying that corrective signal to the camera while operating the camera for long term target integration periods in essentially the same manner and exposure time to produce a corrected television scan signal, and using that corrected signal to reproduce an image. A television camera system is disclosed for automatically implementing this process, which system includes a vertical interval control circuit responsive to a time selector and start input to generate the control signals to the camera for gating off the scan, a first scan signal, gating signals (using flip-flops driven from the horizontal and vertical scan signals) and gates to feed only the video signals from the central portion of the scan raster to an inverse peak and hold circuit which develops the corrective signal, and the second scan signal so that the corrective television signal can be generated and recorded or otherwise employed.

摘要翻译： 公开了一种自动导出和使用黑电平控制信号用于长期目标集成摄像机系统的系统和方法。 该方法采用以下步骤：以预选的曝光时间，以长期目标积分方式首先操作照相机，并检测并保持从该扫描得到的电视视频信号的反峰值电平， 目标，从保持的反峰值电平产生校正信号，并以基本上相同的方式和曝光时间以相同的方式和曝光时间在相机操作相机的同时将该校正信号应用于相机，以产生校正的电视扫描信号，并使用该信号 校正信号以再现图像。 公开了一种用于自动实现该过程的电视摄像机系统，该系统包括响应于时间选择器和起始输入的垂直间隔控制电路，以产生用于选通扫描的照相机的控制信号，第一扫描信号，选通信号（ 使用从水平和垂直扫描信号驱动的触发器）和门仅将来自扫描光栅的中心部分的视频信号馈送到产生校正信号的反向峰值和保持电路，以及第二扫描信号，使得 校正电视信号可以产生和记录或以其它方式使用。

公开(公告)号：US4517683A

公开(公告)日：1985-05-14

申请号：US336134

申请日：1981-12-31

申请人： Fred W. Caspari

发明人： Fred W. Caspari

IPC分类号： H03M9/00 ,  H03K13/24

CPC分类号： H03M9/00

摘要： Apparatus for decoding a serial data stream having remote control informations. Detector means for detecting a serial data stream containing said remote control data are provided to supply a microprocessor with serial data. The microprocessor employs the programming steps of sampling the data at a rate in excess of two times the data rate. The number of consecutive samples of zero bits between samples of a one bit are as counted. A register is loaded with a one bit every time a one is sampled, and loaded with a zero bit when the number of consecutive zeros exceed a predetermined number.

摘要翻译： 用于解码具有遥控信息的串行数据流的装置。 提供用于检测包含所述遥控数据的串行数据流的检测器装置，以向微处理器提供串行数据。 微处理器采用编程步骤，以超过数据速率的两倍的速率对数据进行采样。 一位的采样之间的零位的连续样本数被计数。 每当一个采样时，寄存器被加载一位，当连续零的数量超过预定数量时，寄存器被加载一个零位。

公开(公告)号：US3946329A

公开(公告)日：1976-03-23

申请号：US476645

申请日：1974-06-05

申请人： Fred W. Caspari

发明人： Fred W. Caspari

IPC分类号： H03L7/16 ,  H03J7/18 ,  H03J7/20 ,  H03J7/28 ,  H03L7/18 ,  H04B1/26 ,  H04N5/44 ,  H03B3/04

CPC分类号： H03J7/28

摘要： Apparatus and method for providing an automatic frequency tuning system capable of supplying a local oscillator signal with a preselected frequency. The frequency of an output signal of the local oscillator is electronically varied across a frequency region which includes the preselected frequency. The output signal of the local oscillator is combined with the output signal of a reference signal generator. After the combination of the local oscillator signal with the reference oscillator signal produces a preestablished condition which is the result of the local oscillator signal attaining the preselected frequency, the frequency of the local oscillator signal is held constant. The local oscillator signal is thereafter compared to the reference oscillation signal and a change in the local oscillator signal frequency is corrected by means of an automatic frequency control feedback loop containing a discriminator circuit.BACKGROUND OF THE INVENTION1. Field of the InventionThis invention relates generally to apparatus for automatically tuning an oscillator to a preselected frequency, and more particularly to an automatic tuning circuit for use with a plurality of information-bearing frequency channels systematically dispersed throughout a range of frequencies. Upon identification of a condition resulting for the attainment of the preselected frequency by the oscillator output signal, an automatic frequency control (AFC) circuit is used to stabilize the frequency of the oscillator signal.2. Description of the Prior ArtAn automatic frequency control circuit typically is comprised of a local oscillator, a signal mixing circuit such as a heterodyne conversion transducer, an amplifier tuned to a predetermined intermediate frequency and a discriminator circuit designed to operate about the predetermined intermediate frequency. The output signal of the discriminator controls the frequency of the output signal of the local oscillator. A received signal, for which demodulation is desired, is typically applied to the mixing circuit. The combination of the received signal and the local oscillator signal produces an intermediate frequency signal which is applied to the tuned amplifier. The output signal of the local oscillator is used to convert the received signal and the relationship between the local oscillator signal frequency and the received signal frequency is stabilized by the circuit.It is known in the prior art to provide an AFC circuit with mechanical apparatus for providing the coarse adjustment of the local oscillator. The coarse adjustment typically places the intermediate frequency signal within the operating range of the tuned amplifier and the discriminator circuit. The AFC circuit thereafter provides the vernier tuning for the satisfactory demodulation of the received signal. Because of problems associated with deterioration of mechanical apparatus, it is desirable to provide coarse adjustment by elctronic means.The characteristics of the tuned amplifier and more importantly, the discriminator circuit, provide the limit for the range over which a received signal can be stabilized and demodulated. Providing an expanded frequency range for these characteristics, for example to provide greater signal tuning capability, would increase the possibility of identifying and demodulating an undesired signal falling within the range of the amplifier and discriminator characteristics.Furthermore, in conventional AFC circuits, the loss of the received signal, which contributes to the intermediate frequency signal, can produce undesirable drift in the frequency of the local oscillator output signal.There are many applications, such as commercial broadcast television, where the received signal (i.e. the signal transmitted by the television station) is rigidly controlled. The AFC circuit originally was provided to minimize the effects on the operation of a television receiver of frequency shifts in the local oscillator. Shifts of the broadcast signals are unimportant, so that the necessity for utilizing the received signal in the AFC loop is minimized. It is desirable, however, to provide for control of the local oscillator by the received signal, the reference signal controlling the local oscillator output signal frequency in the absence of the received signal.It is therefore an object of the present invention to provide an improved automatic frequency tuning circuit.It is another object of the present invention to provide an automatic frequency tuning circuit capable of electronic coarse adjustment over a preestablished frequency spectrum.It is a further object of the present invention to provide an automatic electronic frequency tuning circuit for information-bearing channels in a wide frequency range without compromising fine tuning capability.It is yet another object of the present invention to provide apparatus for stabilizing a local oscillator output signal by means of an AFC circuit during temporary loss of received signal.It is a more particular object of the present invention to provide a voltage controlled oscillator and a controllable voltage source in an automatic frequency tuning circuit for sweeping the frequency of the oscillator signal across a frequency spectrum in which at least one desired information-bearing frequency band is located.It is still another particular object of the present invention to provide apparatus for suspending scanning over a range of frequencies by an oscillator signal in an AFC circuit at a frequency determined by a reference frequency signal.It is yet another particular object of the present invention to provide apparatus for comparing a signal having a varying frequency with a reference frequency signal in order to identify a predetermined frequency of the varying signal.It is yet another object of the present invention to provide an electronic automatic frequency tuning circuit with a reference freqeuncy signal, which maintains a substantially constant oscillator frequency during loss of the received signal.It is yet a further object of the present invention to provide an electronic automatic frequency tuning circuit having a first feedback loop for identifying a predetermined oscillator signal frequency and a second feedback loop for maintaining the predetermined oscillator signal.It is a still further object of the present invention to provide an electronic automatic frequency tuning circuit which, upon entry of data, can identify and maintain an oscillator signal having a frequency determined by the entered data.It is yet another particular object of the present invention to provide an AFC circuit utilizing a received signal for control of the local oscillator, the local oscillator controlled by a reference signal in the absence of the received signal.It is another object of the present invention to provide for relatively rapid response for circuits controlling scanning of a frequency region by the output signal of a local oscillator, while providing a relatively slow response for stabilization of signals stabilizing the frequency of the local oscillator output signal.It is yet another object of the present invention to provide an amplifier permitting the same discriminator circuit to be used in an AFC circuit with a beat frequency signal above and with a beat frequency signal below the frequency of the reference signal generator being utilized by the AFC circuit.SUMMARY OF THE INVENTIONThe aforementioned and other objects are accomplished, according to the present invention, by an electronic automatic frequency tuning circuit comprising two sets of apparatus for controlling the signal of variable frequency local oscillator. The first set of apparatus varies the frequency of the local oscillator until a predetermined relationship between the local oscillator signal and a reference generator signal is identified. Upon identification of the predetermined relationship, the second set of apparatus stabilizes the frequency of the oscillator output signal at substantially constant value. To stabilize the frequency of the oscillator signal, the reference generator signal and the local oscillator signal are combined and a resulting difference frequency signal applied to a discriminator. The discriminator provides an output signal which applies a control signal to the oscillator resulting in oscillator signal frequency corrections compensating for changes in the oscillator signal frequency.The automatic frequency tuning circuit is not dependent on the received signal, the signal for which demodulation is typically desired, and therefore a loss of the received signal does not affect the frequency of the oscillator signal. However, in the presence of the received signal, an AFC circuit utilizing the received signal controls the frequency of the local oscillator output signal.The reference oscillator can be apparatus for producing a comb of harmonic frequencies. By varying the controllable oscillator signal frequency beginning at a known initial value, the number of signals resulting from a preselected relationship, e.g. predetermined beat frequencies, occurring between the reference oscillator signal and the variable oscillator can be used to determine the predetermined relationship. Apparatus is provided for increasing and for decreasing the frequency of the local oscillator. In the AFC circuit utilizing the oscillator and generator signals, an amplifier is utilized permitting a single discriminator circuit to be employed with either the beat frequency falling above or the beat frequency falling below the related reference generator component.These and other features of the invention will be understood upon reading of the following description along with the drawings.

摘要翻译： 一种用于提供能够以预选频率提供本地振荡器信号的自动频率调谐系统的装置和方法。 本地振荡器的输出信号的频率在包括预选频率的频率区域内电子变化。 本地振荡器的输出信号与参考信号发生器的输出信号相结合。 本地振荡器信号与参考振荡器信号的组合产生预定的状态，这是本振信号达到预选频率的结果，本振信号的频率保持不变。 然后本地振荡器信号与参考振荡信号进行比较，并且通过包含鉴频电路的自动频率控制反馈回路校正本地振荡器信号频率的变化。

公开(公告)号：US4020419A

公开(公告)日：1977-04-26

申请号：US476503

申请日：1974-06-05

申请人： Fred W. Caspari ,  Wayne C. Johnson

发明人： Fred W. Caspari ,  Wayne C. Johnson

IPC分类号： H03J7/18 ,  H03J5/02 ,  H03J7/02 ,  H03J7/06 ,  H03J7/28 ,  H03L7/06 ,  H03L7/181 ,  H04B1/26 ,  H04N5/44 ,  H03B3/08

CPC分类号： H03J7/06 ,  H03J5/0245

摘要： An all electronic tuning system is described for establishing a frequency of a local oscillator in a television receiver. When a channel selection is made, a number representing the desired channel is entered in a memory circuit. A first plurality of frequencies is generated in response to a channel selection, and a VCO employed as a local oscillator is caused to increase in frequency. When the VCO frequency differs from the first plurality of frequencies by a predetermined amount, a second plurality of frequencies is generated. Each frequency generated in said second plurality of frequencies is compared with said VCO frequency. When a predetermined difference exists between said VCO frequency and said second plurality of frequencies, a count is recorded. When the recorded count is equivalent to the number obtained in the memory circuit, the VCO tuning is inhibited and the VCO frequency is stabilized until a subsequent channel selection is made.

摘要翻译： 描述了用于在电视接收机中建立本地振荡器的频率的全电子调谐系统。 当进行频道选择时，表示期望频道的号码被输入到存储器电路中。 响应于信道选择产生第一多个频率，并且使用作为本地振荡器的VCO频率增加。 当VCO频率与第一多个频率不同预定量时，产生第二多个频率。 将在所述第二多个频率中产生的每个频率与所述VCO频率进行比较。 当在所述VCO频率和所述第二多个频率之间存在预定的差异时，记录计数。 当记录的计数等于在存储器电路中获得的数量时，VCO调谐被禁止，并且VCO频率稳定，直到进行随后的频道选择。

公开(公告)号：US4020484A

公开(公告)日：1977-04-26

申请号：US638567

申请日：1975-12-08

申请人： Fred W. Caspari

发明人： Fred W. Caspari

IPC分类号： G09G5/24 ,  H04N5/45 ,  G06F3/14

CPC分类号： G09G5/24 ,  H04N5/45

摘要： Apparatus and method for generating a size-controllable, segmented character for use with a television receiver. The character generator can be used to display the television channel number to which a television receiver is tuned. Associated apparatus is provided for endowing a displayed character with a cursive slant. The apparatus controlling the size of the displayed character can be set to cause the character to continuously diminish, after a predetermined time, eventually disappearing.The character segments are defined by clocking apparatus related to the horizontal and vertical scan of a television display unit. In addition from horizontal and vertical clocks enabling all possible character segments, enabling signals are generated by the receiver apparatus specifying particular segments of a desired character.

摘要翻译： 用于产生用于电视接收机的尺寸可控的分段字符的装置和方法。 字符发生器可用于显示电视接收机调谐到的电视频道号码。 提供了相关的装置，用于赋予具有草书斜面的显示字符。 可以设置控制显示字符的大小的装置，使得在预定时间之后，字符将不断地减少，最终消失。