公开(公告)号：US06243368B1

公开(公告)日：2001-06-05

申请号：US08999362

申请日：1997-12-29

申请人： Emad N. Farag

发明人： Emad N. Farag

IPC分类号： H04B7216

CPC分类号： H04B1/001 ,  H04W72/00 ,  H04W72/02 ,  H04W72/0453

摘要： A method and apparatus are provided for selecting a digital channel from a composite digital signal which is made up of a plurality of digital channels. The method is accomplished by assigning two frequency bands of a plurality of frequency bands to each of the plurality of digital channels, wherein the two frequency bands overlap. A filtering process is accomplished by selecting a filter, from a group of filters, the selected filter corresponding to one of the frequency bands. The selected filter is then applied to the composite digital signal.

摘要翻译： 提供一种从由多个数字通道组成的复合数字信号中选择数字信道的方法和装置。 该方法通过将多个频带的两个频带分配给多个数字信道中的每一个来实现，其中两个频带重叠。 通过从一组滤波器中选择对应于一个频带的所选滤波器来实现滤波处理。 然后将所选择的滤波器应用于复合数字信号。

公开(公告)号：US6111531A

公开(公告)日：2000-08-29

申请号：US866585

申请日：1997-05-30

申请人： Emad N. Farag

发明人： Emad N. Farag

IPC分类号： H03M3/02 ,  H03M3/00

CPC分类号： H03M3/40 ,  H03M3/43

摘要： A bandpass sigma-delta modulator includes a first low pass sigma-delta modulator of a predetermined order and operative according to a predetermined transfer characteristic for producing a first output of an initial dynamic range. A second low pass sigma-delta modulator substantially similar to the first low pass sigma-delta modulator is disposed in parallel relationship with the first modulator. Cross-coupled connections between the first and second modulators are operative to alter the respective transfer characteristics such that the first and second low pass modulator outputs cooperate to form the bandpass transfer function and expand the dynamic range beyond that associated with the individual modulators.

摘要翻译： 带通Σ-Δ调制器包括预定次序的第一低通Σ-Δ调制器，并根据用于产生初始动态范围的第一输出的预定传输特性来操作。 基本上类似于第一低通Σ-Δ调制器的第二低通Σ-Δ调制器与第一调制器并联设置。 第一和第二调制器之间的交叉耦合操作可操作以改变相应的传输特性，使得第一和第二低通调制器输出协作以形成带通传递函数并且将动态范围扩展到与各个调制器相关联的动态范围。