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7 条记录 (耗时 0.008 秒)

    Selective fading transformer
    1.
    发明授权
    Selective fading transformer 失效
    选择性渐变变压器

    公开(公告)号：US3605019A

    公开(公告)日：1971-09-14

    申请号：US3605019D

    申请日：1969-01-15

    申请人： IBM

    发明人： CUTTER JOSEPH T ,  DAVIES JOHN M ,  FREEMAN DON G ,  SCHWARZ GORDON R ,  VANBLERKOM RICHARD

    IPC分类号： H04B7/04 ,  H04B15/00

    CPC分类号： H04B7/04

    摘要： The invention is a communication system which causes errors introduced by selective frequency fading channels to be time localized. It does this by transmitting the Fourier transform of the baseband signal. The preferred embodiment consists of a frequency division multiplexor multiplexing a plurality of channels and a Fourier transformer taking the Fourier transform of the digital representation of the resultant waveform. The Fourier transform is reconverted into an analog representation by a D-A converter and transmitted by means of an A-D converter. The receiver reconverts the analog representation of the Fourier transform into a digital signal, a Fourier transformer takes the inverse transform, as a D-A converter, reconverts the digital representation back into an analog waveform and then an FDM demodulator demultiplexes the analog waveform resulting in a signal representative of the input to the transmitter with errors introduced by the channels appearing as burst errors (time localized).

    Real time digital fourier analyzer
    2.
    发明授权
    Real time digital fourier analyzer 失效
    实时数字分析仪

    公开(公告)号：US3591784A

    公开(公告)日：1971-07-06

    申请号：US3591784D

    申请日：1968-10-17

    申请人： IBM

    发明人： CUTTER JOSEPH T ,  FREEMAN DON G ,  BLERKOM RICHARD VAN

    IPC分类号： G06F17/14 ,  G06F7/38

    CPC分类号： G06F17/142

    摘要： A real time digital Fourier analyzer utilizing either the Cooley-Tukey or the Danielson-Lanczos algorithms consisting of particularly adapted hardware to facilitate the calculations of said algorithms. Specifically, the preferred embodiment utilizes hardware equally adapted to both algorithms with fixed point arithmetic, a look-ahead two''s complementor, and an address generator employing three binary counters.

    Digital fm receiver
    4.
    发明授权
    Digital fm receiver 失效
    数字FM接收器

    公开(公告)号：US3609555A

    公开(公告)日：1971-09-28

    申请号：US3609555D

    申请日：1967-07-19

    申请人： IBM

    发明人： BLERKOM RICHARD VAN ,  FREEMAN DON G ,  CRUTCHFIELD RICHARD C

    IPC分类号： H03D3/02 ,  H03D3/00

    CPC分类号： H03D3/02

    摘要： A digital FM receiver for receiving information in the form of analog signals on a frequency-modulated carrier at its input and providing said information in digital form at its output. The input signal consisting of a subcarrier modulated by the analog information (baseband) is converted into digital form in an analog to digital converter and is then demodulated in a digital demodulator, providing at its output the baseband information in digital form. The invention herein described was made in the course of or under a contract with the United States Air Force.