公开(公告)号：US07180951B2

公开(公告)日：2007-02-20

申请号：US11204530

申请日：2005-08-16

Applicant: Kevin T. Chan

Inventor： Kevin T. Chan

IPC: H04B3/00

CPC classification number: H04B3/23 ,  H04B3/32 ,  H04L25/0272 ,  H04L25/085

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions multi-transmitter system for unshielded twisted pair (UTP) data communication applications. For each transmitter, digital transmit data is converted to a current-mode differential signal analog waveform by a digital-to-analog converter (DAC). The output current from each DAC is used to generate the required transmit voltage on the respective UTP line. Timing circuitry staggers the time base of each transmitter to reduce the aggregate EMI emissions of the multi-transmitter system.

Abstract translation: 用于非屏蔽双绞线（UTP）数据通信应用的功率高效和降低的电磁干扰（EMI）发射多发射机系统。 对于每个发射器，数字发射数据由数模转换器（DAC）转换为电流模式差分信号模拟波形。 来自每个DAC的输出电流用于在相应的UTP线路上产生所需的发射电压。 定时电路交错了每个发射机的时基，以减少多发射机系统的总EMI辐射。

公开(公告)号：US06958648B2

公开(公告)日：2005-10-25

申请号：US10928371

申请日：2004-08-30

Applicant: Felix Cheung ,  Kevin T. Chan ,  Siavash Fallahi

Inventor： Felix Cheung ,  Kevin T. Chan ,  Siavash Fallahi

IPC: H03G1/00 ,  H03F1/36

CPC classification number: H03G1/0088

Abstract: A programable gain amplifier (PGA) has an amplifier and a variable resistor that is connected to the output of the amplifier. The variable resistor includes a resistor that is connected to a reference voltage and multiple parallel taps that tap off the resistor. A two-stage switch network having fine stage switches and coarse stage switches connects the resistor taps to an output node of the PGA. The taps and corresponding fine stage switches are arranged into two or more groups, where each group has n-number of fine stage switches and corresponding taps. One terminal of each fine stage switch is connected to the corresponding resistor tap, and the other terminal is connected to an output terminal for the corresponding group. The coarse stage switches select from among the groups of fine stage switches, and connect to the output of the PGA. During operation, one selected tap is connected to the output of the PGA by closing the appropriate fine stage switch and coarse stage switch, where the selected tap defines a selected group of the fine stage switches. Additionally, one fine stage switch is closed in each of the non-selected groups of fine stage switches. In one embodiment, the location of the closed switches in the non-selected groups is the mirror image of the location in an adjacent group. This reduces the transient voltages that occur when tap selection changes from one group to another.

Abstract translation: 可编程增益放大器（PGA）具有放大器和连接到放大器的输出的可变电阻器。 可变电阻器包括连接到参考电压的电阻器和分离电阻器的多个并联抽头。 具有精细级开关和粗级开关的两级开关网络将电阻抽头连接到PGA的输出节点。 抽头和相应的精细级开关被布置成两组或更多组，其中每组具有n个细级开关和相应的抽头。 每个精细级开关的一个端子连接到相应的电阻抽头，另一个端子连接到相应组的输出端子。 粗级开关从精细级开关组中选择，并连接到PGA的输出。 在运行期间，一个选择的分接头通过关闭适当的细级开关和粗级开关连接到PGA的输出，其中所选择的分接头定义了选定的精细级开关组。 此外，每个非选择的精细级开关组中的一个精细级开关闭合。 在一个实施例中，未选择组中的闭合开关的位置是相邻组中位置的镜像。 这样可以减少轻敲选择从一个组变为另一组时发生的瞬态电压。

公开(公告)号：US06373908B2

公开(公告)日：2002-04-16

申请号：US09375834

申请日：1999-08-16

Applicant: Kevin T. Chan

Inventor： Kevin T. Chan

IPC: H04B110

CPC classification number: H04B3/32 ,  H04B1/586 ,  H04B3/23 ,  H04L12/10

Abstract: An adaptive electronic transmission signal cancellation circuit for separating transmit data from receive data in a bidirectional communication system operating in full duplex mode is disclosed. The output of a main transmitter responsive to a first bias current is connected to the output of a receiver through an internal resistor. A first replica transmitter responsive to a second bias current and matched to the main transmitter current gain and rise/fall time characteristics is connected to the input terminal of the receiver, and produces a cancellation voltage between the output terminal of the main transmitter and the input terminal of the receiver as a function of the second bias current and the internal resistor. A second replica transmitter matched to the current gain and rise/fall time characteristics of the main transmitter and the first replica transmitter and responsive to the second bias current is connected to the output terminal of the main transmitter for canceling excess current, developed by the first replica transmitter, at the output terminal of the main transmitter.

公开(公告)号：US06259745B1

公开(公告)日：2001-07-10

申请号：US09429893

申请日：1999-10-29

Applicant: Kevin T. Chan

Inventor： Kevin T. Chan

IPC: H04B1500

CPC classification number: H04L25/08 ,  H04B3/23 ,  H04B3/32 ,  H04L12/10 ,  H04L25/0276 ,  H04L25/0282 ,  H04L25/0286 ,  H04L25/03834 ,  H04L25/14

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions transmitter for unshielded twisted pair (UTP) data communication applications. Transmit data is processed by a digital filter. The digital filter output data is converted to a current-mode analog waveform by a digital-to-analog converter (DAC). The digital filter is integrated with the DAC binary decoder in a memory device such as a ROM with time multiplexed output. DAC line driver cells are adaptively configurable to operate in either a class-A or a class-B mode depending on the desired operational modality. A discrete-time analog filter is integrated with the DAC line driver to provide additional EMI emissions suppression. An adaptive electronic transmission signal cancellation circuit separates transmit data from receive data in a bidirectional communication system operating in full duplex mode. For a multi-transmitter system, timing circuitry staggers the time base of each transmitter to reduce the aggregate EMI emissions of the multi-transmitter system.

Abstract translation: 用于非屏蔽双绞线（UTP）数据通信应用的功率高效和降低的电磁干扰（EMI）发射器。 发送数据由数字滤波器处理。 数字滤波器输出数据通过数/模转换器（DAC）转换为电流模式模拟波形。 数字滤波器与DAC二进制解码器集成在诸如具有时间复用输出的ROM的存储器件中。 DAC线路驱动器单元可以自适应地配置，以根据所需的操作模式在A类或B类模式下工作。 离散时间模拟滤波器与DAC线路驱动器集成，以提供额外的EMI发射抑制。 自适应电子传输信号消除电路在全双工模式下工作的双向通信系统中分离发送数据与接收数据。 对于多发射机系统，定时电路交错了每个发射机的时基，以减少多发射机系统的总EMI辐射。