-
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。
-
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。
-
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。
-
公开(公告)号：US4283792A
公开(公告)日：1981-08-11
申请号：US25034
申请日：1979-03-29
CPC分类号： H03D3/20 , H03D1/2254 , H03J7/04 , H04N5/50 , H03D13/008 , H03D2200/0009 , H03D2200/0049 , H03D2200/0082
摘要： In a system in which an intermediate frequency signal is synchronously detected using an intermediate frequency carrier signal derived from the intermediate frequency signal by means of a tuned circuit and a limiter circuit to remove amplitude variations therefrom, an automatic fine tuning signal is derived in a phase detector to which are fed the intermediate frequency carrier signal after its phase has been shifted 90 degrees in a phase shifter and either the intermediate frequency signal or the intermediate frequency carrier signal. When the intermediate frequency carrier signal is used in the phase detector, a second tuned circuit is used therein and buffering between the two tuned circuits prevents interaction therebetween.
摘要翻译： 在使用通过调谐电路从中频信号导出的中频载波信号和限幅器电路同步检测中频信号的系统中，以消除其振幅变化，在相位中导出自动微调信号 检测器在其相位在移相器中被移位90度之后被馈送到中频载波信号，以及中频信号或中频载波信号。 当在相位检测器中使用中频载波信号时，在其中使用第二调谐电路，并且两个调谐电路之间的缓冲阻止它们之间的相互作用。
-
公开(公告)号：US3987317A
公开(公告)日：1976-10-19
申请号：US635365
申请日：1975-11-26
申请人： Masayuki Hongu , Shigeru Ohmuro , Hiromi Kawakami
发明人： Masayuki Hongu , Shigeru Ohmuro , Hiromi Kawakami
CPC分类号： H03F1/302
摘要： A transistor biasing circuit having a single biasing transistor for biasing first and second operational transistors. The biasing transistor has means connecting its base to its collector and means are provided to connect the base of each of the first and second operational transistors to the collector circuit of the biasing transistor. Each of the three transistors are arranged in a circuit between a pair of voltage terminals which are connected to a power supply. The arrangement of the resistors in the circuit paths of the biasing transistor and the operational transistors are in such a way as to provide circuit means for stabilizing the collector currents of the first and second transistors regardless of variations in the factor of h.sub.FE. This circuit arrangement provides an improved stabilization of the collector currents over prior art devices.
摘要翻译： 一种晶体管偏置电路，具有用于偏置第一和第二操作晶体管的单个偏置晶体管。 偏压晶体管具有将其基极连接到其集电极的装置，并且提供装置以将第一和第二操作晶体管中的每一个的基极连接到偏置晶体管的集电极电路。 三个晶体管中的每一个被布置在连接到电源的一对电压端子之间的电路中。 偏置晶体管和操作晶体管的电路中的电阻器的排列方式是提供用于稳定第一和第二晶体管的集电极电流的电路装置，而与hFE因子的变化无关。 该电路布置提供了集电极电流相对于现有技术装置的改进的稳定性。
-
公开(公告)号：US4419695A
公开(公告)日：1983-12-06
申请号：US341465
申请日：1982-01-21
IPC分类号： H04N5/60
CPC分类号： H04N5/607
摘要： A television sound receiver having an input terminal for receiving a television sound signal, a tuner including a local oscillator connected to the input terminal, an intercarrier sound demodulating circuit connected to the tuner, a split-carrier sound demodulating circuit, including a limiter amplifier connected to the tuner, a sound signal output terminal, and a switching device for selectively and operatively connecting either the intercarrier or split-carrier sound demodulating circuits between the tuner and the sound signal output terminal. Additionally, the receiver includes an error detecting device connected to the split-carrier sound demodulating circuit for detecting the frequency error of the local oscillator and a first operational device which is responsive to an output signal from the error detecting device and which produces a first operational device output signal which activates the switching device such that the split-carrier sound demodulating circuit is operatively connected between the tuner and the sound output terminal when the output signal from the error detecting device is less than a predetermined level. Level detectors are connected to the limiter amplifier and detect a level of the split-carrier sound signal. A second operational device, which is responsive to the output signal from the level detectors, produces an output signal which activates the switching device such that the intercarrier sound demodulating circuit is operatively connected between the tuner and the sound output terminal when the output signals from the level detectors are less than a predetermined value.
摘要翻译： 一种具有用于接收电视声音信号的输入端子的电视声音接收器，包括连接到输入端子的本地振荡器的调谐器，连接到调谐器的载波间声音解调电路，分离载波声音解调电路，包括限幅放大器 调谐器，声音信号输出端子和用于选择性地和可操作地连接调谐器和声音信号输出端子之间的载波间或分离载波声音解调电路的开关装置。 此外，接收机包括连接到分离载波声音解调电路以检测本地振荡器的频率误差的误差检测装置和响应于来自错误检测装置的输出信号并且产生第一操作的第一操作装置 装置输出信号，其激活开关装置，使得当来自误差检测装置的输出信号小于预定电平时，分离载波声音解调电路可操作地连接在调谐器和声音输出端子之间。 电平检测器连接到限幅放大器并检测分离载波声音信号的电平。 响应于来自电平检测器的输出信号的第二操作装置产生激活开关装置的输出信号，使得当来自所述开关装置的输出信号时，载波间声音解调电路可操作地连接在调谐器和声音输出端子之间 电平检测器小于预定值。
-
公开(公告)号：US4777526A
公开(公告)日：1988-10-11
申请号：US58403
申请日：1987-06-05
IPC分类号： G08B13/196 , H04N7/18
CPC分类号： G08B13/19645 , G08B13/19697 , H04N7/181
摘要： A security monitor system is designed to transmit video signals from a plurality of video information sources via a common transmission line. Video information from respective video information sources is scanned at given timings to check the monitoring areas in a given order. An automatic recognition may be facilitated in the security monitor system for detecting substantial and noticable movement within a picture derived from the video information from each of the video signal sources. Therefore, the security monitor system is inexpensive and satisfactory for monitoring a plurality of monitoring areas and is satisfactory for recording video information of a variety of monitoring areas, when movement in the picture of one of the monitoring areas is detected, by means of a video tape recorder or other appropriate recording means.
摘要翻译： 安全监视器系统被设计为经由公共传输线从多个视频信息源传送视频信号。 在给定的定时扫描来自相应视频信息源的视频信息，以给定的顺序检查监视区域。 在安全监控系统中可以方便地进行自动识别，用于检测来自每个视频信号源的视频信息的图片内的实质上和可观的移动。 因此，安全监控系统便宜且满意地监视多个监视区域，并且当检测到监视区域之一的图像中的移动时，通过视频来记录各种监视区域的视频信息是令人满意的 磁带录音机或其他适当的录音手段。
-
-
-
-
-
-
搜索结果
7 条记录 (耗时 0.017 秒)
