公开(公告)号：US3883727A

公开(公告)日：1975-05-13

申请号：US26904872

申请日：1972-07-05

申请人： STUART RICHARD L ,  BHOPALE ARVIND M

发明人： STUART RICHARD L ,  BHOPALE ARVIND M

IPC分类号： H03H17/02 ,  G06F1/02 ,  G06F15/34

CPC分类号： H03H17/0289 ,  H03H2218/12

摘要： A multi-level digital filter system applicable to modems is provided. The incoming data is read serially into M shift registers and read out in parallel by M further shift registers under the control of an M-bit clock, where M log2N and N is the number of levels. After appropriate conditioning by a logic control circuit, the parallel outputs are filtered separately by M digital shaping filters. The shaping filters each comprise a chain of shift registers the outputs of which are weighted by a resistor network and summed to produce a desired time response, which in an exemplary embodiment is the inverse Fourier transform of an ideal low-pass filter. Summing of the filter outputs produces an N-level signal.

摘要翻译： 提供了适用于调制解调器的多级数字滤波系统。 输入数据被串行读入M个移位寄存器，并在M位时钟控制下由M个另外的移位寄存器并行读出，其中M = log2N，N是电平数。 在通过逻辑控制电路适当调节之后，并行输出由M个数字整形滤波器分开滤波。 整形滤波器各自包括一组移位寄存器，其输出由电阻网络加权，并相加以产生期望的时间响应，其在示例性实施例中是理想低通滤波器的傅里叶逆变换。 滤波器输出的相加产生N电平信号。