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    Apparatus and robust method for detecting tones
    4.
    发明授权
    Apparatus and robust method for detecting tones 失效
    用于检测音调的装置和鲁棒方法

    公开(公告)号：US5325427A

    公开(公告)日：1994-06-28

    申请号：US857552

    申请日：1992-03-23

    申请人： Rajiv S. Dighe

    发明人： Rajiv S. Dighe

    IPC分类号： H04L27/00 ,  H04L27/30 ,  H04Q1/45 ,  H04Q1/453 ,  H04Q1/457 ,  H04Q1/46 ,  H04M3/00

    CPC分类号： H04Q1/453 ,  H04L27/30 ,  H04Q1/457 ,  H04Q1/46 ,  H04M7/1295

    摘要： A robust tone detector is realized by applying a single taper, which provides a relatively narrow bandwidth filter, to a received signal and, then, performing a Discrete Fourier Transform of the tapered signal. The result of the Fourier transform is used to obtain an estimate of energy in the frequency domain of the expected tone. A prescribed selection algorithm based on the relationship of the received signal energy in the time domain and the energy estimate in the frequency domain is used to determine whether a valid tone has been received. Robustness of the tone detector is improved by performing a plurality of Discrete Fourier Transforms of the single tapered version of the received signal at a corresponding plurality of frequencies relative to the nominal frequency of an expected one or more tones. A further improvement in the tone detector is obtained by the dynamically adjusting tone acceptance thresholds based on a measure of channel impairments.

    摘要翻译： 通过对接收到的信号应用提供相对窄带宽滤波器的单个锥度，然后执行锥形信号的离散傅里叶变换，实现鲁棒的音调检测器。 傅立叶变换的结果用于获得预期音调的频域中的能量估计。 使用基于时域中的接收信号能量与频域中的能量估计的关系的规定的选择算法来确定是否已经接收到有效的音调。 通过相对于期望的一个或多个音调的标称频率以对应的多个频率执行接收信号的单个锥形版本的多个离散傅立叶变换来提高音调检测器的鲁棒性。 通过基于信道损伤的测量来动态地调整音调接受阈值来获得音调检测器的进一步改进。

    Packet route scheduling in a packet cross connect switch system for periodic and statistical packets
    5.
    发明授权
    Packet route scheduling in a packet cross connect switch system for periodic and statistical packets 失效
    分组交叉连接交换机系统中的分组路由调度用于周期性和统计分组

    公开(公告)号：US5042032A

    公开(公告)日：1991-08-20

    申请号：US371233

    申请日：1989-06-23

    申请人： Rajiv S. Dighe ,  Carl J. May, Jr.

    发明人： Rajiv S. Dighe ,  Carl J. May, Jr.

    IPC分类号： H04L12/56

    CPC分类号： H04L45/22 ,  H04L45/00 ,  H04L45/20 ,  H04L45/302 ,  H04L49/102 ,  H04L49/25 ,  H04L49/254

    摘要： Routing of packets in a packet cross-connect switch is determined based on the particular type of packet, i.e., statistical or periodic, grade of service assigned to the packet, e.g., minimum delay, the actual queuing delay at output assigned to the particular packet destination and the status of the assigned output ports. Additionally, for periodic type packets the routing decision is also based on whether an interval is reserved for transmission of periodic packets at the assigned output ports. The routing decision is also based under certain conditions on whether or not the packet has been previously scheduled over an alternate route. The actual queuing delay at the assigned output ports is compared to predetermined delay threshold values in determining the packet route and/or whether it should be discarded. If the packet is a statistical type and it was previously scheduled over an alternate route, it will be discarded, if it is not scheduled to be routed via a primary one of the assigned output ports and the delay at a secondary, i.e., alternate, one of the assigned output ports is greater than a predetermined re-routing delay threshold value. In a specific embodiment, the delay threshold values are selected such that typically only statistical packets are scheduled for an alternate route. Periodic packets are typically scheduled for an alternate route or discarded only for catastrophic failures.

    Link based alternative routing scheme for network restoration under failure
    6.
    发明授权
    Link based alternative routing scheme for network restoration under failure 失效
    基于链路的替代路由方案，用于故障时的网络恢复

    公开(公告)号：US6141319A

    公开(公告)日：2000-10-31

    申请号：US630808

    申请日：1996-04-10

    申请人： Rajiv S. Dighe ,  Qiang Ren ,  Bhaskar Sengupta

    发明人： Rajiv S. Dighe ,  Qiang Ren ,  Bhaskar Sengupta

    IPC分类号： H04L12/56 ,  H04Q11/04 ,  H04J3/14

    CPC分类号： H04L45/22 ,  H04L45/00 ,  H04L45/18 ,  H04L45/20 ,  H04L45/28 ,  H04Q11/0478 ,  H04L2012/562 ,  H04L2012/5627

    摘要： Alternative routing schemes in high-speed networks ensure fault tolerance in the event of a link failure. An heuristic algorithm, based on maximal-flow algorithm, is first used to partition the network into parts: one part carries regular or primary traffic and another part is reserved to carry re-routed traffic in the event of a link failure. The result of applying the algorithm is used to find alternative routes for a given call at the time of call setup. The scheme can be modified to accommodate hop-court limitations and loop avoidance.

    摘要翻译： 高速网络中的替代路由方案可确保链路故障时的容错能力。 基于最大流算法的启发式算法首先用于将网络划分为部分：一部分承载常规或主流量，另一部分保留在链路故障的情况下携带重路由流量。 应用该算法的结果用于在呼叫建立时查找给定呼叫的替代路由。 该方案可以修改以适应跳地场限制和循环避免。

    Packet cross connect switch system including improved throughput
    7.
    发明授权
    Packet cross connect switch system including improved throughput 失效
    分组交叉连接交换机系统包括提高吞吐量

    公开(公告)号：US5001706A

    公开(公告)日：1991-03-19

    申请号：US371237

    申请日：1989-06-23

    申请人： Rajiv S. Dighe ,  Carl J. May, Jr.

    发明人： Rajiv S. Dighe ,  Carl J. May, Jr.

    IPC分类号： H04L12/56

    CPC分类号： H04L12/56

    摘要： Improved throughput is realized in a packet cross-connect switch by including an addressable memory unit in each of a plurality of input ports for storing packets and by allowing each of a plurality of output ports to address directly any one of the input ports to obtain a particular packet stored therein, which is destined for the output port. To this end, the input ports supply the packet destination and starting address of the packet stored in their memory to a scheduler. The scheduler controllably selects an output port assigned to the packet destination and supplies packet output information to the selected output port including the packet starting address and the identity of the input port storing the packet. When a particular output port is ready to obtain a particular packet, it addresses the memory unit in the particular input port to read the first packet word. The addressed packet word is supplied via a data bus to the requesting output port. Thereafter, the packet address is incremented by one packet word at a time and the corresponding packet words are read out of the input port memory units until the entire packet has been supplied to the requesting output port.

    Multiple queue bandwidth reservation packet system
    8.
    发明授权
    Multiple queue bandwidth reservation packet system 失效
    多队列带宽预留分组系统

    公开(公告)号：US4979165A

    公开(公告)日：1990-12-18

    申请号：US371235

    申请日：1989-06-23

    申请人： Rajiv S. Dighe ,  Carl J. May, Jr.

    发明人： Rajiv S. Dighe ,  Carl J. May, Jr.

    IPC分类号： H04L12/64

    CPC分类号： H04L12/64

    摘要： A multiple queue packet bandwidth reservation arrangement is disclosed in which statistical type packets are scheduled for transmission and a prescribed interval is reserved for transmission of periodic type packets for each scheduled statistical packet. Each arriving statistical packet is assigned a scheduled time of service based on the amount of packet information already queued to be supplied as an output and the duration of any intervals reserved for transmission of periodic packets at an assigned output port. Operation of the bandwidth reservation arrangement is such that normally a statistical packet is not delayed from being transmitted at its scheduled time of service for more than an interval needed to transmit a maximum length periodic packet.