Subscriber loop range extender
    4.
    发明授权
    Subscriber loop range extender 失效
    订户循环范围扩展

    公开(公告)号:US3671676A

    公开(公告)日:1972-06-20

    申请号:US3671676D

    申请日:1969-12-17

    CPC classification number: H04M19/006

    Abstract: This disclosure describes a telephone subscriber loop range extender having a signaling mode and a transmission mode. In the former, a resistive shunt is applied across the loop with each dial pulse to aid operation of the pulsing relay for an originating cell. For a terminating call, the shunt is applied upon answer, either during ringing or during the silent interval, to aid operation of the ring-trip relay. In the transmission mode, voice frequency gain and greater transmitter voltage are applied to the loop. A control circuit consisting of logic, timing and relay driving circuits, acts upon loop voltage and current data to control shunt action and mode selection.

    Abstract translation: 本公开描述了具有信令模式和传输模式的电话用户环路扩展器。 在前者中,每个拨号脉冲在环路上施加电阻分流器,以帮助起始电池的脉冲继电器的操作。 对于终止呼叫,在应答时应用分路,无论是在振铃期间还是在静音间隔期间,都可以应用分流来帮助环路继电器的操作。 在传输模式下,语音频率增益和更大的发射机电压被施加到环路。 由逻辑,定时和继电器驱动电路组成的控制电路作用于环路电压和电流数据,以控制分流动作和模式选择。

    Secret transmission of intelligence
    10.
    发明授权
    Secret transmission of intelligence 失效
    秘密传播情报

    公开(公告)号:US3897591A

    公开(公告)日:1975-07-29

    申请号:US45632242

    申请日:1942-08-27

    CPC classification number: H04K1/02

    Abstract: 1. In a signal privacy system, means to convert a gradually varying signal current wave into a stepped wave, means to superpose on said stepped wave a masking current varying in magnitude in a manner unrelated to the signal to produce a stepped summation current wave for transmission, and means to eliminate short portions of the summation wave at the points where the steps occur to further conceal the signal.

    Abstract translation: 在信号隐私系统中,用于将逐渐变化的信号电流波转换成阶梯波的装置意味着在所述阶梯波上叠加屏蔽电流,该屏蔽电流以与信号无关的方式在幅度上变化以产生阶梯式求和电流波, 传输,以及在步骤发生的点处消除求和波的短部分以进一步隐藏信号的装置。

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