公开(公告)号：US06621346B1

公开(公告)日：2003-09-16

申请号：US09314764

申请日：1999-05-19

申请人： Joseph T. Nabicht ,  Kazi I. Islam ,  Donald C. Richardson ,  Subahashish Mukherjee

发明人： Joseph T. Nabicht ,  Kazi I. Islam ,  Donald C. Richardson ,  Subahashish Mukherjee

IPC分类号： H03G310

CPC分类号： H04L27/0002 ,  H04B3/145 ,  H04B3/23 ,  H04L5/023 ,  H04L25/03878

摘要： Digital subscriber modems (8, 15) for use in Asynchronous Digital Subscriber Line (ADSL) communications are disclosed. The central office modem (8) includes a digital transceiver function (10) and an analog front end function (12), where the analog front end function (12) is integrated into a single integrated circuit. According to the disclosed embodiments, the analog front end function (12) includes a transmit and a receive side. On the receive side, an impedance matching circuit (56) is coupled to the input of a programmable gain amplifier (54C). The impedance matching circuit (56) is controlled by the same control signals (C1, C2, C3) as used to select the gain of the programmable gain amplifier (54C), so that a constant input impedance is presented to the signal input (RXP), independent of the selected gain.

摘要翻译： 公开了用于异步数字用户线（ADSL）通信的数字用户调制解调器（8,15）。 中央办公室调制解调器（8）包括数字收发器功能（10）和模拟前端功能（12），其中模拟前端功能（12）被集成到单个集成电路中。 根据所公开的实施例，模拟前端功能（12）包括发送和接收侧。 在接收侧，阻抗匹配电路（56）耦合到可编程增益放大器（54C）的输入端。 阻抗匹配电路（56）由用于选择可编程增益放大器（54C）的增益的相同的控制信号（C1，C2，C3）来控制，使得恒定的输入阻抗被呈现给信号输入端 ），独立于所选增益。

公开(公告)号：US06226322B1

公开(公告)日：2001-05-01

申请号：US09050620

申请日：1998-03-30

申请人： Subahashish Mukherjee

发明人： Subahashish Mukherjee

IPC分类号： H03H730

CPC分类号： H04L27/0002 ,  H04B3/145 ,  H04B3/23 ,  H04L5/023 ,  H04L25/03878

摘要： Digital subscriber modems (8, 15) for use in Asynchronous Digital Subscriber Line (ADSL) communications are disclosed. Each modem includes a digital transceiver function (10, 13) and an analog front end function (10, 11), where the analog front end function (10, 11) is integrated into a single integrated circuit. According to the disclosed embodiments, the analog front end functions (10, 11) each include a transmit and a receive side. The transmit side includes oversampled registers (44C, 44R) and digital filters (46C, 46R) which serve to increase the sample rates of the digital data to be transmitted, so that the analog-to-digital converter (48C, 48R) operates in an oversampled manner, and so that the downstream analog low pass filters (50C, 50R) can be realized with relatively simple, low-order filters. On the receive side, digital filter functions (64C, 64R) are included downstream from the analog-to-digital converters (62C, 62R), to minimize the complexity of the receive-side analog filters (58C, 58R). The remote DSL modem (8) also includes an equalizer function (57) to boost the signal amplitude with increasing frequency, to overcome the effects of line attenuation on the high frequency downstream transmissions.

摘要翻译： 公开了用于异步数字用户线（ADSL）通信的数字用户调制解调器（8,15）。 每个调制解调器包括数字收发器功能（10,13）和模拟前端功能（10,11），其中模拟前端功能（10,11）被集成到单个集成电路中。 根据所公开的实施例，模拟前端功能（10,11）各自包括发送端和接收侧。 发射侧包括过采样寄存器（44C，44R）和数字滤波器（46C，46R），其用于增加要发送的数字数据的采样率，使得模数转换器（48C，48R）在 过采样方式，并且可以用相对简单的低阶滤波器来实现下游模拟低通滤波器（50C，50R）。 在接收侧，数字滤波器功能（64C，64R）被包括在模数转换器（62C，62R）的下游，以最小化接收侧模拟滤波器（58C，58R）的复杂性。 远程DSL调制解调器（8）还包括均衡器功能（57），用于以增加的频率升高信号幅度，以克服线路衰减对高频下游传输的影响。