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181 条记录 (耗时 0.013 秒)

    Circuit for independently adjusting frequency deviation of a VCO
    51.
    发明授权
    Circuit for independently adjusting frequency deviation of a VCO 失效
    独立调节VCO频偏的电路

    公开(公告)号：US4531155A

    公开(公告)日：1985-07-23

    申请号：US436369

    申请日：1982-10-25

    申请人： Kenichi Hasegawa

    发明人： Kenichi Hasegawa

    IPC分类号： H03C3/06 ,  G11B20/06 ,  H03C3/02 ,  H04N5/40 ,  H04N5/922 ,  H04N1/32 ,  H04B1/04

    CPC分类号： H03C3/02 ,  H04N5/40

    摘要： A circuit for controlling the application of a signal source to a variable frequency oscillator is disclosed in which the width of frequency deviation and the lower limit frequency of the modulated signal can be set independently of each other. The emitter of a first transistor is connected to a first voltage source through a first resistor. Its base is connected to a signal source through a capacitor, and also to a second voltage source through a switch circuit. The base of a second transistor is connected to the second voltage source and its emitter is connected to the first voltage source through a variable resistor. The emitters of the first and second transistors are connected with each other by a third resistor. The collector current of the second transistor is supplied to a variable frequency oscillator.

    摘要翻译： 公开了一种用于控制向可变频率振荡器施加信号源的电路，其中可以彼此独立地设置调制信号的频率偏差和下限频率的宽度。 第一晶体管的发射极通过第一电阻器连接到第一电压源。 其基极通过电容器连接到信号源，并且还通过开关电路连接到第二电压源。 第二晶体管的基极连接到第二电压源，其发射极通过可变电阻器连接到第一电压源。 第一和第二晶体管的发射极通过第三电阻器相互连接。 第二晶体管的集电极电流被提供给可变频率振荡器。

    Deviation detector for FM video recording system
    52.
    发明授权
    Deviation detector for FM video recording system 失效
    FM录像系统偏差探测器

    公开(公告)号：US4476498A

    公开(公告)日：1984-10-09

    申请号：US346370

    申请日：1982-02-05

    申请人： David A. Sheean

    发明人： David A. Sheean

    IPC分类号： G01R23/00 ,  H03C3/02 ,  H03C3/06 ,  G11B27/36 ,  H04N5/76

    CPC分类号： H03C3/02 ,  G01R23/00

    摘要： The deviation of an FM signal modulated by a video signal is detected by measuring the average period of the FM signal at a measurement rate proportional to the average frequency of the FM signal. The value of each average period measurement is compared with a predetermined number to produce an indicator signal each time the measured value is less than or equal to the predetermined number. The effect of overshoot of the video signal due to preemphasis is minimized by detecting the successive occurrence of at least two indicator signals to provide a further indicator signal which may be used for visually monitoring video peak levels and/or for protecting a utilization device to which the FM signal is supplied.

    摘要翻译： 通过以与FM信号的平均频率成比例的测量速率测量FM信号的平均周期来检测由视频信号调制的FM信号的偏差。 将每个平均周期测量的值与预定数量进行比较，以在每次测量值小于或等于预定数量时产生指示符信号。 通过检测至少两个指示符信号的连续出现来提供视频监视视频峰值电平和/或用于保护使用设备到达哪个 提供FM信号。

    Phase compressor for phase modulated signal
    53.
    发明授权
    Phase compressor for phase modulated signal 失效
    用于相位调制信号的相位压缩器

    公开(公告)号：US4021742A

    公开(公告)日：1977-05-03

    申请号：US652613

    申请日：1976-01-26

    申请人： Yukihiko Machida

    发明人： Yukihiko Machida

    IPC分类号： H03C3/00 ,  H03C3/02 ,  H03C3/06 ,  H03D20060101 ,  H03D3/00 ,  H03D3/18 ,  H04N9/66 ,  H03D3/02

    CPC分类号： H04N9/66 ,  H03C3/02 ,  H03D3/18

    摘要： A phase compressor for a phase modulated signal comprises n phase suppressors (n is an integer greater than 2), each of which includes an adder and a limiter. The n phase suppressors are connected in series with one another. In this case, outputs from the limiters of nth, (n - 1)th, (n - 2)th, . . . . 2nd phase suppressors are individually supplied to the adders along with outputs from the (n - 1)th, (n - 2)th, . . . . 1st phase suppressors, respectively. A reference signal is supplied to the adder of the nth phase suppressor, by which a modulated phase angle of the phase modulated signal with a wide modulation index is phase-compressed by 1/.sub.n.sub.+1. The phase compressed signal is phase-demodulated by a phase demodulator without decreasing a signal-noise ratio.

    摘要翻译： 用于相位调制信号的相位压缩器包括n个相位抑制器（n是大于2的整数），每个相位抑制器包括加法器和限幅器。 n相抑制器彼此串联连接。 在这种情况下，来自第n，（n-1），（n-2）th的限制器的输出。 。 。 。 第二相位抑制器与第（n-1），（n-2），...的输出分别提供给加法器。 。 。 。 第一相抑制器。 参考信号被提供给第n个相位抑制器的加法器，相位调制信号的相位调制信号的调制相位角被相位压缩1 / n + 1。 相位压缩信号由相位解调器进行相位解调而不降低信噪比。

    Narrowband receiving system with improved signal to noise ratio
    54.
    发明授权
    Narrowband receiving system with improved signal to noise ratio 失效
    具有提高信噪比的窄带接收系统

    公开(公告)号：US3911365A

    公开(公告)日：1975-10-07

    申请号：US30124272

    申请日：1972-10-26

    申请人： LICENTIA GMBH

    发明人： MAURER ROBERT ,  LOCHERER KARL-HEINZ

    IPC分类号： H03F7/00 ,  H03D1/04 ,  H03D3/00 ,  H04B1/10 ,  H04B1/16 ,  H04B1/26 ,  H04B1/30 ,  H03C3/06

    CPC分类号： H04B1/30 ,  H03D1/04 ,  H03D3/00 ,  H03D3/004

    摘要： In a receiver system for high frequency signals which are either AM or FM modulated with a low frequency signal, which receiver system has at least a mixer stage and a demodulator and an input band width which is so narrow that the received high frequency signal can just be transmitted without distortion, the signal to noise ratio of the receiver system is reduced to below the value one by feeding back a portion of the demodulated low frequency signal to the oscillator of the mixer.

    摘要翻译： 在用低频信号进行AM或FM调制的高频信号的接收机系统中，哪个接收机系统至少具有混频器级和解调器以及输入带宽如此狭窄，使得接收到的高频信号只能 通过将解调的低频信号的一部分反馈到混频器的振荡器，无损失地发送，接收机系统的信噪比被降低到低于值1。