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公开(公告)号：US4370676A
公开(公告)日：1983-01-25
申请号：US277739
申请日：1981-06-26
摘要： A synchronous detector for detecting an information signal modulated onto a carrier, such as a video IF signal, is disclosed in which there are provided a circuit for supplying the modulated information signal in the form of a vestigial sideband signal, a filter circuit coupled to the supplying circuit which includes a tuning circuit tuned to the frequency of the carrier on which the information signal is modulated, an emitter follower circuit connected to the output of the filter circuit, a limiter circuit connected to the filter circuit, for producing a switching carrier, and a multiplier having first and second input terminals coupled to the output of the limiter circuit and to the supplying circuit, for multiplying the modulated information signal and the switching carrier to obtain said information signal. In one embodiment, the limiter circuit includes a differential amplifier having first and second transistors, base electrodes of which are connected to the emitter follower circuit, and third and fourth common base transistors, emitter electrodes of which are respectively connected to collector electrodes of the first and second transistors and collector electrodes of which provide output terminals for supplying the switching carrier.
摘要翻译： 公开了一种用于检测调制到诸如视频IF信号的载波上的信息信号的同步检测器，其中提供了一种用于以残留边带信号的形式提供调制信息信号的电路，耦合到 提供电路，其包括调谐到信号信号被调制的载波的频率的调谐电路，连接到滤波器电路的输出的射极跟随器电路，连接到滤波器电路的限幅器电路，用于产生开关载体， 以及乘法器，其具有耦合到限幅器电路的输出和供给电路的第一和第二输入端，用于将调制信息信号和开关载波相乘以获得所述信息信号。 在一个实施例中，限幅器电路包括具有第一和第二晶体管的差分放大器，其基极连接到射极跟随器电路，以及第三和第四公共基极晶体管，其发射电极分别连接到第一和第二晶体管的集电极 并且其第二晶体管和集电极提供用于提供开关载体的输出端子。
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公开(公告)号：US4631589A
公开(公告)日：1986-12-23
申请号：US642334
申请日：1984-08-20
IPC分类号： H04N5/16
CPC分类号： H04N5/165
摘要： A dark signal component below a predetermined level of a video signal is varied such that a dark peak level is made to coincide with a pedestal level by feedback control. According to this configuration, a signal component toward a white level side above the predetermined level is not changed by dark restoration, thus obtaining stable color reproduction and stable brightness which are not affected by the dark restoring operation.
摘要翻译： 改变低于视频信号的预定电平的暗信号分量，使得通过反馈控制使暗峰电平与基座电平一致。 根据该结构，通过暗恢复不会改变朝向高于预定电平的白电平侧的信号分量，从而获得不受暗恢复操作影响的稳定的色彩再现和稳定的亮度。
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公开(公告)号：US4238771A
公开(公告)日：1980-12-09
申请号：US886427
申请日：1978-03-14
摘要： A muting circuit for a television or AM signal receiver which uses a synchronous detector.The muting circuit includes an input terminal for receiving an amplitude modulated signal, a synchronous detector for detecting such AM signal, a circuit for supplying a reference signal having a predetermined frequency and phase to the synchronous detector, an amplifier, a circuit path for delivering to the amplifier the detected signal produced by the synchronous detector, a level detecting device connected to the output of the synchronous detector for producing an excess signal when the detected signal exceeds a predetermined level, an integrator for producing a muting signal in response to the production over an extended period of time of the excess signal, and a switching device connected to the amplifier for muting the signal produced by the amplifier in response to the production of the muting signal.
摘要翻译： 一种使用同步检波器的电视或AM信号接收机的静音电路。 静音电路包括用于接收幅度调制信号的输入端子，用于检测这种AM信号的同步检波器，用于向同步检测器提供具有预定频率和相位的参考信号的电路，放大器，用于传送到 放大器由同步检测器产生的检测信号，电平检测装置连接到同步检测器的输出端，用于当检测信号超过预定电平时产生过量信号;积分器，用于响应于生产过程产生静噪信号 多余信号的延长的时间段以及连接到放大器的开关装置，用于根据产生的静噪信号使由放大器产生的信号静音。
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4.发明授权
公开(公告)号：US4156255A
公开(公告)日：1979-05-22
申请号：US833710
申请日：1977-09-15
CPC分类号： H03J7/045 , H03D1/2281 , H04B1/26
摘要： A television receiver has an automatic fine tuning circuit with a first phase-locked loop including a first low pass filter and a synchronous video detector with a second phase-locked loop including a second low pass filter. The cut off frequency of the first low pass filter is selected lower than the cut-off frequency of the second low pass filter, thereby enabling a stable operation of two phase-locked loops simultaneously.
摘要翻译： 电视接收机具有自动微调电路，其具有包括第一低通滤波器和同步视频检测器的第一锁相环，其具有包括第二低通滤波器的第二锁相环。 第一低通滤波器的截止频率选择为低于第二低通滤波器的截止频率，从而能够同时稳定地操作两个锁相环。
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公开(公告)号：US4163196A
公开(公告)日：1979-07-31
申请号：US891279
申请日：1978-03-29
摘要： Demodulating apparatus for a modulated signal comprised of a carrier deriving circuit which is supplied with the modulated signal and which derives an unmodulated carrier therefrom, the carrier deriving circuit including a tuned circuit having a center frequency substantially coincident with the carrier frequency of the modulated signal and a limiter circuit in which the limiter circuit imparts a phase shift to the signal supplied thereto in connection with its elimination of the amplitude fluctuations in the signal produced by the tuned circuit. A synchronous detector receives the modulated signal and the derived carrier so as to detect the modulated signal with the derived carrier. A phase shift circuit supplies the synchronous detector with a phase shifted modulated signal, the phase shift substantially compensating for the phase shift imparted by the limited circuit in the carrier deriving circuit, whereby the modulated signal and the carrier which are applied to the synchronous detector are substantially in phase with each other.
摘要翻译： 一种调制信号的解调装置，包括一个载波导出电路，该载波导出电路被提供有调制信号，并从其中导出未调制的载波，该载波导出电路包括调谐电路，该调谐电路的中心频率与调制信号的载波频率基本一致， 限制器电路，其中限制器电路相对于消除由调谐电路产生的信号中的振幅波动而向所提供的信号施加相移。 同步检测器接收调制信号和导出载波，以便用导出的载波检测调制信号。 相移电路为同步检波器提供相移调制信号，相移基本上补偿由载波导出电路中的受限电路产生的相移，由此调制信号和施加到同步检波器的载波是 基本上彼此同相。
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公开(公告)号：US4263675A
公开(公告)日：1981-04-21
申请号：US88852
申请日：1979-10-29
摘要： An automatic fine tuning (AFT) circuit includes a frequency discriminator for discriminating an intermediate frequency signal, a capacitor supplied with the discriminated intermediate frequency signal to produce an AFT voltage thereacross, a comparator circuit for comparing the AFT voltage with a reference voltage, a first switching transistor controlled by the comparator circuit and which supplies and charges the capacitor with the reference voltage during a channel selection operation when the AFT voltage is less than the reference voltage, a second switching transistor controlled by the comparator circuit and which connects the capacitor to ground to discharge the same during a channel selection operation when the AFT voltage is greater than the reference voltage, and a third switching transistor for rendering the comparator circuit operative during a channel selection operation and inoperative during an AFT operation.
摘要翻译： 自动微调（AFT）电路包括用于鉴别中频信号的鉴频器，提供有鉴别中频信号的电容器以产生其上的AFT电压，用于将AFT电压与参考电压进行比较的比较器电路，第一 开关晶体管由比较器电路控制，并且当AFT电压小于参考电压时，在通道选择操作期间向电容器供给和充电电容器，由比较器电路控制并将电容器连接到地的第二开关晶体管 当AFT电压大于参考电压时，在频道选择操作期间对其进行放电;以及第三开关晶体管，用于使比较器电路在频道选择操作期间工作，并且在AFT操作期间不起作用。
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公开(公告)号：US4234963A
公开(公告)日：1980-11-18
申请号：US906406
申请日：1978-05-16
摘要： A synchronous detector adapted to detect a modulated information signal, such as a video IF signal. The modulated information signal is provided in the form of a vestigial sideband signal. A band-pass filter including a tuned circuit tuned to the frequency of the carrier on which the information signal is modulated has a pass band which is less than the frequency spectrum of the vestigial sideband signal so as to limit the frequency spectrum of the signal passed by the filter to a double sideband signal. A limiter is coupled to the band-pass filter to receive the double sideband signal and for deriving a switching carrier therefrom, the frequency of the switching carrier being equal to the frequency of the carrier on which the information signal is modulated. An emitter-follower circuit is connected between the band-pass filter and the limiter so as to couple the double sideband signal from the filter to the limiter. A multiplier circuit has first input terminals coupled to the limiter for receiving the derived switching carrier and second input terminals for receiving the modulated information signal, whereby the modulated information signal is multiplied with the switching carrier to obtain the information signal.
摘要翻译： 一种适用于检测诸如视频IF信号的调制信息信号的同步检测器。 调制信息信号以残留边带信号的形式提供。 包括被调谐到信号信号被调制的载波的频率的调谐电路的带通滤波器具有小于残留边带信号的频谱的通带，以限制通过的信号的频谱 通过滤波器到双边带信号。 限幅器耦合到带通滤波器以接收双边带信号并从其导出交换载波，切换载波的频率等于信息信号被调制的载波的频率。 射频跟随器电路连接在带通滤波器和限幅器之间，以将来自滤波器的双边带信号耦合到限幅器。 乘法器电路具有耦合到限幅器的第一输入端子，用于接收导出的切换载波和用于接收调制信息信号的第二输入端，由此将调制信息信号与切换载波相乘以获得信息信号。
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公开(公告)号：US4110635A
公开(公告)日：1978-08-29
申请号：US715630
申请日：1976-08-18
CPC分类号： H03D1/229 , H03F3/04 , H03F3/42 , H03F3/45089 , H04N5/455
摘要： An amplifier provides a complete video and sound I.F. signal to a synchronous detector switching circuit, and the switching signal to be applied to the switching circuit is obtained from the same amplifier by connecting a grounded base stage, with its emitter impedance, in series with the amplifier load. The grounded base stage has a load tuned to the I.F. carrier frequency, and the filtered signal from the grounded base is the signal applied as the switching signal to the synchronous detector switching circuit.
摘要翻译： 放大器提供完整的视频和声音I.F. 信号发送到同步检测器开关电路，并且通过将接地基站与发射极阻抗串联连接到放大器负载，从同一放大器获得施加到开关电路的开关信号。 接地基座有一个负载调谐到I.F. 载波频率，并且来自接地基极的滤波信号是作为切换信号施加到同步检波器开关电路的信号。
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公开(公告)号：US4673983A
公开(公告)日：1987-06-16
申请号：US915397
申请日：1986-10-06
CPC分类号： H04N5/45
摘要： In a picture-in-picture television receiver, the subpicture signal is A-D converted; the converted digital subpicture signal is latched in response a subpicture clock in synchronism with a subpicture synchronizing signal; the latched signal is latched again and stored in an image memory in response to a main picture synchronizing signal; and the latched signal is read from the image memory in synchronism with the main picture synchronizing signal, in order that the subpicture can stably be inserted in a predetermined area of the main picture by eliminating the unstable data duration during which variation in the subpicture signal is different for each bit signal thereof.
摘要翻译： 在画中画电视接收机中，子画面信号被A-D转换; 经转换的数字子画面信号与子画面同步信号同步地响应于子画面时钟被锁存; 锁存信号被再次锁存并响应于主图像同步信号而存储在图像存储器中; 并且与主画面同步信号同步地从图像存储器中读取锁存信号，以便通过消除子图像信号变化的不稳定数据持续时间，子画面可以稳定地插入主画面的预定区域 对于其每个位信号而言是不同的。
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公开(公告)号：US4322751A
公开(公告)日：1982-03-30
申请号：US89908
申请日：1979-10-31
CPC分类号： H04N5/62
摘要： A synchronous detector suitable for use in a color television receiver detects both a video signal and an audio IF signal, but in a fashion in which these two signals do not interfere with one another. In the detector, a tuner provides an IF signal in which the video signal and audio or sound IF signals are modulated on a carrier; a signal generator, such as a phase-locked loop, provides both a detecting signal synchronized with the carrier of the IF signal, and a comparing signal having the same frequency as the carrier of the IF signal but phase-shifted .pi./2 therefrom; a synchronous detecting circuit for synchronously detecting the IF signal by the detecting signal to produce the video signal; and a phase comparator for phase comparing the IF signal with the comparing signal to provide the sound IF signal. In one arrangement, the phase comparator provides a filtered version of the sound IF signal as an AFT control signal to control the fine tuning of the tuner. In another embodiment, two phase comparators are included so that the sound IF signal and the AFT control signal are provided separately.
摘要翻译： 适用于彩色电视接收机的同步检测器检测视频信号和音频IF信号，但是以这两个信号彼此不干扰的方式。 在检测器中，调谐器提供IF信号，其中视频信号和音频或声音IF信号在载波上被调制; 诸如锁相环的信号发生器提供与IF信号的载波同步的检测信号，以及具有与IF信号的载波相同但与其相移的pi / 2的频率相同的频率的比较信号; 同步检测电路，用于通过检测信号同步检测IF信号以产生视频信号; 以及相位比较器，用于将IF信号与比较信号进行相位比较，以提供声音IF信号。 在一种布置中，相位比较器提供声音IF信号的滤波版本作为AFT控制信号，以控制调谐器的微调。 在另一个实施例中，包括两个相位比较器，使得分别提供声音IF信号和AFT控制信号。
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