Telephone privacy system
    1.
    发明授权
    Telephone privacy system 失效
    电话隐私系统

    公开(公告)号:US3912868A

    公开(公告)日:1975-10-14

    申请号:US49512443

    申请日:1943-07-17

    CPC classification number: H04K1/02

    Abstract: 1. In a system for transmitting indications of an electrical quantity of varying magnitude, means to transmit indications in the form of stepped values each corresponding approximately to the magnitude of the quantity at the corresponding time, means to compare the respective stepped values against the true values of the quantity to determine the residues of the true values over and above said stepped values in each case, and means to separately transmit indications of said residues.

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