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7 条记录 (耗时 0.006 秒)

    A/D converter
    3.
    发明公开
    A/D converter 失效
    A / D转换器

    公开(公告)号：EP0195502A3

    公开(公告)日：1988-01-13

    申请号：EP86300702

    申请日：1986-02-03

    申请人： STC PLC

    发明人： Vance, Ian Alistair Ward

    IPC分类号： H03D03/00 ,  H03D01/24

    CPC分类号： H03D1/24 ,  H03D3/006 ,  H03D3/007 ,  H03D2200/005 ,  H03D2200/0054

    摘要： An analogue-to-digital converter arrangement including a signal de-emphasis network 10 1 . 10 o which attenuates higher frequency analogue signals relative to lower frequency analogue signals, and A/D converter 11 1 , 11 o to which the de-emphasised signals are applied, and a pre-emphasis network 12 l , 12 0 substantially complementary to the de-emphasis network to which the digitised signals are applied.

    摘要翻译： 一种模数转换器装置，包括信号去加重网络10I，10Q，衰减相对于较低频率模拟信号的较高频率的模拟信号; A / D转换器11I，11Q，其中施加去加重的信号;以及 与被加数字化信号的去加重网络实质上互补的预加重网络12I，12Q。

    Method of, and demodulator for, digitally demodulating an SSB signal
    4.
    发明公开
    Method of, and demodulator for, digitally demodulating an SSB signal 失效
    用于数字解调SSB信号的方法和解调器

    公开(公告)号：EP0206402A3

    公开(公告)日：1988-10-05

    申请号：EP86201011

    申请日：1986-06-11

    申请人： PHILIPS ELECTRONIC AND ASSOCIATED INDUSTRIES LIMITED ,  N.V. Philips' Gloeilampenfabrieken

    发明人： Dewey, Richard James C/o Philips Res. Lab. ,  Collier, Christopher John C/o Philips Res. Lab.

    IPC分类号： H03D01/24

    CPC分类号： H03D1/24

    摘要： In a demodulator a band limited signal from a roofing filter (18) is digitised in an ADC (20) before being applied to quadrature related signal paths (22, 24) including mixers (26, 27) and low pass, decimating filters (28, 29). The output from the decimating filters (28, 29) are applied to a Hilbert transform pair (30, 31). The upper or lower sideband signal is obtained by taking the sum of or the difference between the outputs of the Hilbert transform pair (30, 31). Thereafter the digital signal obtained is reconverted to an analogue signal. By choosing the decimation factor to be an odd numbered integer greater than 1, the periodic transfer function of the output signal has alternate passbands and stopbands. This relaxes the performance requirements of any analogue filters in the receiver and greatly enhances the adjacent channel selectivity of the receiver.

    Active polyphase filters
    5.
    发明公开
    Active polyphase filters 失效
    活性多晶过滤器

    公开(公告)号：EP0185417A3

    公开(公告)日：1988-02-10

    申请号：EP85201957

    申请日：1985-11-26

    申请人： PHILIPS ELECTRONIC AND ASSOCIATED INDUSTRIES LIMITED ,  N.V. Philips' Gloeilampenfabrieken

    发明人： Marshall, Christopher Brian

    IPC分类号： H03H11/04 ,  H03D01/24 ,  H03C01/60

    CPC分类号： H03D1/24 ,  H03C1/60 ,  H03H2011/0494

    摘要： A polyphase filter arrangement in which asymmetric poles and zeros are obtained using feedback. In implementing the polyphase filter arrangement there is provided a feedforward path comprising a first polyphase filter and a feedback path comprising a second polyphase filter. Both filters are preferably two phase filters. In operating the polyphase filter arrangement the loop gain at the unwanted "image" frequency can either be made much greater than unity thereby making the feed forward path insensitive to mismatching or be made much less than unity thereby making the feedback path insensitive to mismatching.