公开(公告)号：US5249225A

公开(公告)日：1993-09-28

申请号：US782402

申请日：1991-10-25

申请人： Arthur B. Williams

发明人： Arthur B. Williams

IPC分类号： H04M1/58

CPC分类号： H04M1/58

摘要： A digitally programmable attenuator balances impedance across a two to four-wire hybrid to reduce echo. The hybrid can interface a two-wire bi-directional telephone line, used for both transmit and receive signals with four-wire circuits having separate unidirectional transmit and receive signal paths. The four-wire circuit interfaces the two-wire circuit through a transformer. Optimum isolation is obtained by setting impedance Z.sub.BAL equal to the impedance of the line including the transformer (Z.sub.LINE). The invention eliminates manual or customized individual adjustment of Z.sub.BAL by a set up technician by use of a digitally controlled attenuator to electronically vary the value of Z.sub.BAL in a highly precise fashion. The programmable attenuator provides an input voltage to a buffer voltage-follower amplifier. The output of the follower amplifier is coupled to a known impedance to limit current flow through the impedance and consequently, current flow through Z.sub.BAL. Data to the attenuator is provided from a DSP programmed to sense and automatically converge to a balanced condition.

摘要翻译： 数字可编程衰减器可以平衡两到四线混合的阻抗，以减少回波。 混合器可以连接双线双向电话线，用于发射和接收信号，四线电路具有单独的单向发射和接收信号路径。 四线电路通过变压器将双线电路接口。 通过设置阻抗ZBAL等于包括变压器（ZLINE）的线路的阻抗来获得最佳隔离。 本发明通过使用数字控制的衰减器以高度精确的方式电子地改变ZBAL的值，由设置技术人员消除了对ZBAL的手动或定制的个人调整。 可编程衰减器向缓冲电压跟随放大器提供输入电压。 跟随放大器的输出耦合到一个已知的阻抗，以限制电流通过阻抗，从而流过ZBAL。 衰减器的数据由编程为感测并自动收敛到平衡状态的DSP提供。

公开(公告)号：US5216704A

公开(公告)日：1993-06-01

申请号：US713824

申请日：1991-06-12

申请人： Arthur B. Williams ,  David T. Lundquist

发明人： Arthur B. Williams ,  David T. Lundquist

IPC分类号： H04M19/00 ,  H04Q11/04

CPC分类号： H04Q11/0435 ,  H04M19/001

摘要： First and second ISDN modems are disposed at a subscriber location and telephone system central office and are arranged to operate in a normal mode, and in a bypass mode upon power failure at the subscriber location. The modems are coupled through the telephone lines via interface transformers having centertaps. The centertap at the subscriber location is split and coupled to a sealing current source and that at the central office is coupled to a sealing current detector and ground. Sealing current flows between the respective transformers during normal operation. A drop in sealing current due to subscriber power failure is sensed at the central office, causing local logic to bypass the central office interface transformer and to couple the central office voice switch directly to the telephone lines. Loop current detectors at the subscriber location and at the central office determine whether the subscriber location voice telephone device is on-hook. If power is restored when on-hook, the local logic recouples the output interface transformer to the telephone lines and the voice telephone device is recoupled to the modem. At the same time, the central office detects whether sealing current has been restored and whether the subscriber voice device is on-hook, and recouples its output interface transformer to the telephone lines and the voice switch to the input interface of the central office modem, resulting in restoration of normal operation.

摘要翻译： 第一和第二ISDN调制解调器设置在订户位置和电话系统中心局处，并且被布置为以正常模式操作，并且在用户位置处于电源故障时处于旁路模式。 调制解调器通过具有centertaps的接口变压器通过电话线耦合。 用户位置处的中心位置分离并耦合到密封电流源，并且在中央局处连接到密封电流检测器和接地。 密封电流在正常运行期间在各变压器之间流动。 在中心局检测到由于用户电源故障引起的密封电流下降，导致本地逻辑绕过中心局接口变压器并将中心局语音交换机直接耦合到电话线路。 用户位置和中心局的环路电流检测器确定用户位置语音电话设备是否挂机。 如果挂机时恢复供电，则本地逻辑将输出接口变压器重新连接到电话线路，语音电话设备被重新连接到调制解调器。 同时，中央办公室检测密封电流是否恢复，用户语音设备是否挂机，并将其输出接口变压器重新连接到电话线和语音切换到中心局调制解调器的输入接口， 导致恢复正常运行。

公开(公告)号：US07365577B2

公开(公告)日：2008-04-29

申请号：US10295304

申请日：2002-11-15

申请人： Kenneth S. Schneider ,  Leo P. Moodenbaugh ,  Arthur B. Williams ,  John E. Meade

发明人： Kenneth S. Schneider ,  Leo P. Moodenbaugh ,  Arthur B. Williams ,  John E. Meade

IPC分类号： H03K3/84

CPC分类号： H03B29/00

摘要： A waveform generator for generating a desired waveform is provided, including a noise kernel configured to store a plurality of samples from a predetermined waveform, the plurality of samples being assigned to a plurality of memory blocks; and an address arrangement configured to randomly select a selected one of the plurality of memory blocks; wherein the noise kernel is configured to communicate the plurality of samples assigned to the selected memory block.

摘要翻译： 提供了一种用于产生期望波形的波形发生器，包括被配置为从预定波形存储多个样本的噪声核，所述多个采样被分配给多个存储块; 以及配置为随机选择所述多个存储块中的所选择的一个的地址排列; 其中所述噪声核被配置为传送分配给所选择的存储器块的所述多个样本。

公开(公告)号：US5550901A

公开(公告)日：1996-08-27

申请号：US295019

申请日：1994-08-24

申请人： Arthur B. Williams

发明人： Arthur B. Williams

IPC分类号： H04M3/00 ,  H04M7/00 ,  H04M9/00 ,  H04M9/08 ,  H04M11/00

CPC分类号： H04M9/003 ,  H04M3/005 ,  H04M7/0096 ,  H04M9/08

摘要： An adapter for interconnecting a tip-ring telephone, a PBX telephone, and a private branch exchange (PBX) is configured to pass out-of-band signals between the PBX telephone and the PBX and to attenuate voice-band signals therebetween when the tip-ring telephone is being used. The adapter includes a band-reject filter and a switching mechanism for connecting the band-reject filter between the PBX telephone and the tip-ring telephone.

摘要翻译： 用于互连尖端电话，PBX电话和专用交换机（PBX）的适配器被配置为在PBX电话和PBX之间传递带外信号，并且当尖端环路电话 正在使用电话。 适配器包括带通滤波器和用于在PBX电话和尖端电话之间连接频带滤波器的切换机构。

公开(公告)号：US4891808A

公开(公告)日：1990-01-02

申请号：US138663

申请日：1987-12-24

申请人： Arthur B. Williams

发明人： Arthur B. Williams

IPC分类号： H04J3/04

CPC分类号： H04J3/047 ,  H04J3/0602 ,  H04J3/0685

摘要： A time division multiplexer is operable to sample data on parallel input channels at a sampling rate at least twice the data rate, to serially transmit the data for each channel in a respective time division, and to recover the data at a receive end. The multiplexer is provided with a bit storage register for successive samples on at least one input channel to be used as a marker channel. Gating connected to the bit storage register forces a detectable unnatural data pattern on the transmitted data for that channel whenever a predetermined bit pattern is stored for that channel. According to one embodiment, when a plurality of unchanged levels (e.g., binary one) appear in the bit storage register, a central bit is inverted to thereby mark that channel. The inverted marker bit is detected and cancelled at the receive end and/or is used to reset the channel counter if detected on a channel other than the marker channel.

摘要翻译： 时分多路复用器可操作以以至少两倍于数据速率的采样率对并行输入通道上的数据进行采样，以在相应时分中串行发送每个通道的数据，并在接收端恢复数据。 复用器设置有用于在至少一个输入通道上用于标记通道的连续采样的位存储寄存器。 连接到位存储寄存器的门控每当存储针对该通道的预定位模式时，强制在该通道的发送数据上的可检测的不自然数据模式。 根据一个实施例，当在位存储寄存器中出现多个未改变的电平（例如，二进制电平）时，中心位被反转，从而标记该通道。 在接收端检测和取消反向标记位，和/或如果在除了标记通道之外的通道上检测到，则用于复位通道计数器。