Showing papers on "Loopback published in 2007"

Systems and methods for network routing in a multiple backbone network architecture

Abstract: Embodiments of a network architecture include a backbone node having a plurality of independent routers or switches connected in a matrix, wherein the matrix includes a plurality of stages of routers or switches, to form a node having a node switching capacity that is greater than the node switching capacity of the individual routers or switches. A method includes assigning one of a plurality of backbone networks to a destination network address, associating a next hop loopback address with the destination network address, and advertising the destination network address in combination with the next hop loopback address through the selected backbone network address.

Fast port failover in a network switch

Abstract: A network switch comprises a port that includes a redirect circuit and a loopback circuit that selectively redirects an egress frame to the redirect circuit when the port is non-operational. The redirect circuit replaces a destination port identifier associated with the egress frame to create a modified frame. The loopback circuit loops back the modified frame in an ingress direction. A transfer circuit transfers the modified frame to another port identified by the destination port identifier.

A loop detection method and device for the network device

Abstract: The invention discloses a loopback detection method, including: for each supported VLAN, the network equipment may respectively create the first loopback detection special message, after the first loopback detection special message for VLANs copied, sent through the port supporting this VLAN; when confirmed that the first port of the network equipment received the first loopback detection special message sent locally, then the first port presents the loopback, and specify the corresponding VLAN to this loopback; according to received second loopback detection special message on the first port, specify the type of loopback for the first port. The invention still discloses the equipment for starting the loopback detection method mentioned above. With the method and equipment in the invention, the loopback detection performance may be improved.

PON with distributed virtual port loopback

Abstract: A passive optical network (PON) access network connected to an external data network can be tested using a remote test host operating on the external data network by looping test data from the test host through the PON to an Optical Network Terminator (ONT), through a data path between an ONT test port and an ONT user port, and back through the PON to the test host. Data tunneling is used to route the data through the external data network between the test host and the PON Optical Line Terminal (OLT). The invention can be used to emulate downstream as well as upstream PON traffic for remote diagnostic testing or other purposes.

System and method of remote testing in loopback mode using mgcp/ncs

Abstract: This invention relates to a system and method of monitoring, by establishing end to end loopback testing across one or more networks with dissimilar transport technologies. The system allows for connection in loopback mode from a standard interface on a test device to a media adaptor located on an IP-based access network, such as a standard multimedia terminal adapter ('MTA'). End-to-End Quality of service delivered over the transmit and receive path can thus be monitored. Loopback tests are initiated from designated endpoints on the network and made operational by attaching a tag to a telephone number, to allow the gateway to signal connection mode to a call agent. The system and method overcome certain inherent limitations of the MGCP/NCS architecture.

Transformer-Coupled Loopback Test for Differential Mixed-Signal Specifications

Abstract: Loopback tests for a differential mixed-signal device under test (DUT) have rarely been attempted, since any imbalance introduced by a design for test (DfT) circuitry on differential signaling delivers an imperfect sinusoidal wave to the DUT input, thereby degrading the DUT performance. In addition, this methodology inherently suffers from fault masking. These problems result in low test accuracy and serious yield loss. This paper presents a novel methodology for efficient prediction of individual DUT dynamic performance parameters with a radio-frequency (RF) transformer in loopback mode to overcome the imbalance problem of DfT circuitry. Cascaded RF transformer in loopback mode produces differently weighted loopback responses, which are used to characterize the DUT dynamic performance. Hardware measurement results show that this approach can be effectively used to predict the specifications of a DUT.

Quadrature modulation transceiver and parameter estimating method for iq imbalance calibration

Abstract: A quadrature modulation transceiver is capable of receiving an in-phase component and a quadrature-phase component corresponding to an input signal, and generating a transmitting signal by up-converting the in-phase component and the quadrature-phase component according to an in-phase transmitting carrier and a quadrature-phase transmitting carrier respectively. The quadrature modulation transceiver then adjusts the transmitting signal using a loopback parameter to generate a loopback signal. Next, the quadrature modulation transceiver down-converts the loopback signal to generate a receiving signal according to an in-phase receiving carrier and a quadrature-phase receiving carrier. Finally, the quadrature modulation transceiver computes calibration parameters of IQ imbalance for the transceiver calibration.

System and method to facilitate real-time end-user awareness in query results through layer approach utilizing end-user interaction, loopback feedback, and automatic result feeder

Abstract: A system and method for facilitating real-time end-user awareness in results to a query to optimize and refine a computerized search utilizing an interactive result layer (IRL) and result operational layer (ROL) are disclosed. The present invention establishes a loopback feedback between encapsulated end-user interactions, which are facilitated through an interactive result layer (IRL), and the results from a query, passed through a result operational layer (ROL). An end-user selects interactions to particular results by way of a prompt within the IRL. The end-user interactions are provided to and processed in the ROL in real-time without the end-user having to re-query the system to reflect said interaction or combination of interactions. A real-time automatic result feeder aides in delivering new results to end-user when results are deleted. Subsequent queries can reflect past end-user interactions.

Method for obtaining transceiver channel transmission time of user terminal

Abstract: The invention discloses a method for obtaining the user terminal transceiving channel transmission time. The physical layer of the user terminal is set to support loop back testing. The switch is set on the emission state by the user terminal. The transmitter channel and receiving channel are in working state at the same time. The transmitter channel of the user terminal sends IQ signal according to the timing reference of the physic layer and records the time which is relative to the time when the timing reference sends the IQ signal. The IQ signal, which is released from the switch, is received by the receiving channel and processed with a physical layer synchronous algorithm to obtain the time of the IQ signal which is relative to the timing reference. The user terminal transceiving channel transmission time is obtained by comparing the time when the IQ signal is sent with the time when the IQ signal is received. The invention obtains the accurate transceiving channel transmission time via the loop back testing on the user terminal, furthermore the time initial lead which is obtained by the user terminal by using the antenna aperture as the reference can be corrected via the transmission time.

Multi-GHz loopback testing using MEMs switches and SiGe logic

Abstract: This paper demonstrates the application of micro-electromechanical switches (MEMs) and SiGe logic devices for passive and active loopback testing of wide data buses at rates up to 6.4Gbps per signal. Target applications include HyperTransport, Fully-Buffered DIMM, and PCIexpress, among others. Recently-commercialized MEMs technology provides high bandwidth (>7GHz) in very small packages in order to support wide parallel buses. SiGe logic also supports >7 Gbps signals when active shaping of the waveform is required. Loopback modules are described with between 9 and 16 differential channels. Multiple cards handle very wide buses or multiple ports. Passive cards utilize MEMs for switching between the Loopback (self-test) mode and traditional ATE source/receiver channels (which are also used for DC parametric tests). It is this switching function that benefits from the MEMs increased density. Active loopback cards provide additional waveform-shaping functions, such as buffering, amplitude attenuation or modulation, deskew, delay adjustment, jitter injection, etc. The modular approach permits pre-calibration of the loopback electronics, and easy reconfiguration between design validation, characterization testing, and high-volume production testing.

Method and Apparatus for Determining Fiber Characteristics in an Optical Communication Network

Abstract: An apparatus and method for deriving fiber characteristics between two nodes in an optical communication network are disclosed. A roundtrip time for a signal to travel between two nodes is measured by sending the signal via the optical supervisory channel from a first node to a second node, which is configured for loopback operation. Fiber characteristics can be calculated based on the measured roundtrip time.

Novel Cross-Loopback Based Test Approach for Specification Test of Multi-Band, Multi-Hardware Radios

Abstract: Recent advances in radio systems engineering have enabled the design of multiple RF front ends (transmitters and receivers), each servicing specific RF communication standards across different frequency bands in a single electronic package. While the design aspects of such radios have been rigorously researched, the test aspects are still evolving. This paper proposes a novel `alternate cross-loopback testing' scheme for a multi-hardware radio using an `optimized' multi-tone test input. In this approach, the transmitter corresponding to one RF standard is used to test receivers corresponding to the same or different communication standards and operating frequency bands. The test approach is compatible with half-duplex operation of the transceiver front-ends and works with all the signal modulation and demodulation software turned "off". Cross-loopback is achieved via a broadband mixer, a programmable VCO and attenuator in the loopback path. The multi-sine tests allow accurate prediction of all transmitter and receiver specifications

Method for optimizing the transmission resources by local loopback in a mobile radio communication cellular network, network and local adapters thereof

Abstract: The invention concerns a method for transmitting data in a mobile radio communication cellular network, which consists in setting up, maintaining and terminating a data communication channel between a caller and a called party located in said cellular network, a caller and/or a called party being each located in a local zone (406) of the cellular network, the setting up, maintaining and termination of the data communication channel using exchanges of signalling messages. According to the invention, said method includes: a first phase of detecting whether the caller and the called party of the communication are located in a common local zone (406) of the cellular network, based on a detection strategy including a step of analyzing all or part of the signalling messages; a second phase of triggering a local loopback operation (421) of all or part of the data exchanged between the caller and the called party, if the detecting phase confirms the local nature of the communication between the caller and the called party.

Co-development of test electronics and PCI Express interface for a multi-Gbps optical switching network

Abstract: This paper presents the design and performance characteristics of a system designed to interface between a PCI Express port and an optical packet switched network as well as provide inline test capability for the whole system. A single lane of PCI Express traffic is inverse multiplexed across eight parallel channels and retransmitted in a burst packet at aggregate data rates of 20 to 36 Gbps. Testing options include loopback self-test, data synthesis and substitution in-line with or in place of system data, and variable channel-to-channel skew. The I/O interfaces also support a range of variable analog parameters such as peak output amplitude, output amplitude swing, and common mode ranges for the input and output to evaluate the performance of or adapt to changes in the opto-electronic components. This design flexibility also allows for use of the system in more conventional electronic applications with little or no required modifications.

Loopback configuration for bi-directional interfaces

Abstract: An interface for implementing a loopback configuration which offers improved calibration and/or testing of an electronic system is disclosed. More specifically, embodiments provide a bi-directional interface with at least two portions or partitions capable of communicating data in opposite directions and implementing a loopback configuration between components of an electronic system, thereby enabling more flexible, efficient and effective calibration and/or testing of the electronic system using a single interface. The loopback of the partitioned bi-directional interface may be used to perform data link training and/or electronic system testing. In one embodiment, the loopback configuration of the interface may be reversible. Additionally, the looped or coupled end of the partitions may be switched from one component to another, thereby reversing the configuration of the loopback in one embodiment. As such, embodiments enable different and/or additional calibration operations and/or tests to be performed when compared with conventional loopback configurations.

Reducing Test Time Using an Enhanced RF Loopback

Abstract: This work presents a method to improve the loopback test used in RF transceivers. The approach is targeted to the System-On-Chip environment, being able to reuse system resources in order to minimize the test overhead. An RF sampler is used during loopback operation, allowing observation of spectral characteristics of the RF signal. While able to improve the overall observability of the RF signal path, faster diagnosis than conventional loopback tests is achieved thanks to a large reduction in the number of transmitted symbols. Theoretical analysis and practical results for a prototype transceiver operating at 846 MHz are presented. It is shown that a significant test time reduction is achievable considering bit error rate tests for common digital modulation schemes.

Go/No-Go Testing of VCO Modulation RF Transceivers Through the Delayed-RF Setup

Abstract: The increasing share of test and packaging as a percentage of the overall cost for RF transceivers necessitate, radically test new approaches to both wafer-level and final production testing We present a new system-level test setup for voltage-controlled oscillator (VCO) modulating transceiver architectures that we call the delayed-RF setup, along with a novel, all-digital design-for-testability (DFT) modification that enables coverage of the most important system-level specifications The delayed-RF setup can be used during wafer sort, thus preventing the packaging of nonfunctional dies Based on this setup and the DFT technique, we present an automatic test development methodology for FM transceivers using frequency-domain signature analysis We develop two distinct pass/fail criteria based on eigensignatures and envelope signatures and a test generation algorithm that aims at minimizing the required delay while attaining full coverage of target faults We develop a fault injection and simulation platform for a VCO-modulation, low-IF transceiver architecture using MATLAB and behavioral models including nonideal response The proposed methodology enables the automation of the test generation process, thus reduces the test development time Experimental results have shown a 90% reduction in the required delay thereby reducing the cost of this test hardware item

Optical fiber loopback test system and method

Abstract: A telecommunications enclosure includes a housing for retaining telecommunication lines therein, the housing including at least one of a splice closure and a terminal closure. At least one of the terminal closure and the splice closure includes a loopback testing station having at least one coupling mounted therein. The coupling is adapted to receive a first terminated end of a first telecommunication line and adapted to receive a second terminated end of a second telecommunication line. The testing station permits loss testing of installed distribution lines at a terminal from a central network facility.

High speed serial crossbar switch based loopback module

Abstract: A loopback module is disclosed in which N differential High Speed Serial (HSS) digital data input channels are received and sent to a serial to parallel converter, whose output is M-bit wide parallel data. By doing so, the effective data rate is divided down by M to 1/M 'fabric' speeds. If the channels contain an embedded clock, the clock is extracted. The parallel data is then sent to a non-blocking crossbar switch, which is able to route any of the N M-bit parallel data inputs to any of Q parallel data outputs by effectively utilizing one multiplexer for each parallel output. Each parallel data output of the crossbar is sent to a parallel to serial converter, whose output is a high speed serial output. Each high speed serial output is fed into a jitter generator circuit, and then to an output driver.

Loopback Signal Cancellation Scheme in the Equalization Digital On-Channel Repeater

Abstract: We analyze the effect of the loopback signal on the equalization digital on-channel repeater (EDOCR) used for single frequency network (SFN), and propose a simple loopback canceller. Simulation results show that the proposed loopback canceller improves the convergence performance of the decision feedback equalizer (DFE) in the EDOCR by eliminating the loopback signal in advance instead of the DFE.

Low-speed optical gate to 2M transmission line multiplexing and switch protective device

Abstract: The utility model discloses a switch device for multiplexing and protecting low-speed optical interface and 2M transmission line The device comprises a photoelectric/electro-optical conversion module, a PCM division multiplexing module, and an automatic circuit switch module, which are electrically connected in sequence The photoelectric/electro-optical conversion module comprises an optical signal input/output module, a coding/decoding module, a clock, a loopback control module and a buffer The PCM division multiplexing module comprises a pulse code modulation multiplex/demultiplex module, a time mark insertion module, a transmission quality analysis module, and a circuit switch module The photoelectric/electro-optical conversion module, the PCM division multiplexing module and the automatic circuit switch module are clock synchronous, and the photoelectric/electro-optical conversion module and the PCM division multiplexing module share one loopback control module The utility model has high communication quality and low maintenance cost

Device for realizing IPV6 cluster broadcast filtration in EPON network by means of hardware loop

Abstract: The utility model discloses an IPV6 multicast filtering device, which is realized based on the EPON network in the way of hardware loopback. The device comprises an ONU chip and a switch chip, the ONU chip comprises an user network interface, and a flushbonding CPU, the switch chip comprises a CPU port, a first switched port and a second switched port, the user network interface is connected with the first switched port, and the CPU port of the switch chip is connected with the second switched port. The utility model realizes MLDSnooping function on the ONU, and needs no additional CPU, instead, the VLAN characteristic of the switch chip is used to makes the CPU port and another port looped back outside, thereby inserting a VLAN label of a special VLANID for the MLD protocol packet, consequently convenient for the ONU chip to capture and process the MLD protocol packet of the data channel in the way of VLANID. Additional hardware does not need to be added, thereby the cost for realizing the method is low.

Real-time end-user aware interactive search utilizing layered approach

Abstract: A system and method for facilitating real-time end-user awareness in results to a query to optimize and refine a computerized search utilizing an interactive result layer (IRL) and result operational layer (ROL) are disclosed. The present invention establishes a loopback feedback between encapsulated end-user interactions, which are facilitated through an interactive result layer (IRL), and the results from a query, passed through a result operational layer (ROL). An end-user selects interactions to particular results by way of a prompt within the IRL. The end-user interactions are provided to and processed in the ROL in real-time without the end-user having to re-query the system to reflect said interaction or combination of interactions. A real-time automatic result feeder aides in delivering new results to end-user when results are deleted. Subsequent queries can reflect past end-user interactions.

Testing sound quality using audio loop back

Abstract: A sound quality test method using audio loopback of a mobile communication terminal and a device are provided to test the sound quality of an MP3 file and a voice signal transmitted/received from a digital terminal embedded with a Bluetooth module by using audio loopback, thereby improving sound quality as reducing time loss for the test. A test signal of a predetermined frequency is generated and transmitted to a mobile communication terminal through a cable or in a short-range wireless communication way(S210,S220). If an audio looped-back signal is inputted from the terminal through the cable or in the short-range wireless communication way, an audio measurement parameter value is calculated by using the test signal and the audio looped-back signal(S230,S240). The audio measurement parameter value is displayed through a display as time information(S250).

Predicting performance parameters of analog and mixed-signal circuits using built-in and built-off self test

Abstract: The widespread use of embedded mixed-signal cores in system-on-chip (SoC) or System-on-Package (SoP) design has been increasingly important in cost-effective manufacturing test for mixed-signal devices. A typical SoP encapsulates many of its internal functions, and its production test is performed by application of test signals to the SoP under control of external Automatic Test Equipment (ATE). However it is a problem that the external ATE does not have direct access to all the internal embedded functions of the SoP. Thus a classical test approach to SoP suffers from limited controllability and observability of its subsystems. Built-in Self-Test (BIST) and Built-Off Self-test (BOST) schemes have been suggested and developed to overcome the limitations of conventional test, such as limited test Input/Output (I/O) accessibility as well as high test cost. However most BIST/BOST approaches have limited test accuracy. The focus of the dissertation is to develop a cost-effective performance-based test methodology based on BIST/BOST, while maintaining the same accuracy as conventional test. This dissertation proposes one BIST approach and two BOST schemes. Our BIST methodology presents a methodology for efficient prediction of circuit specifications with optimized signatures. The proposed Optimized Signature-Based Alternate Test (OSBAT) methodology accurately predicts the specifications of a Device Under Test (DUT) using a strong correlation mapping function. The approach overcomes the limitation that analytical expressions cannot precisely describe the nonlinear relationships between signatures and specifications. Our first BOST approach presents a practical methodology for effective prediction of individual dynamic performance parameters of differential devices with a cascaded Radio-Frequency (RF) transformer in loopback mode. The RF transformer produces differently weighted loopback responses, which are used to characterize the DUT dynamic performance. The approach overcomes the imbalance problem of Design for Test (DfT) circuitry on differential signaling, thereby accurately measuring the dynamic performance of differential mixed-signal circuits. The second BOST scheme is an efficient methodology for accurate prediction of aperture jitter using cost-effective loopback methodology. Aperture jitter is precisely separated from input and clock jitter as well as additive noise present in the DUT, by using an efficient loopback scheme. Hardware measurements were performed for all our approaches, and good results were obtained. This fact verifies that all approaches can be practically used for production test in industry.

Transmission line interface switching method and transmitter

Abstract: PROBLEM TO BE SOLVED: To provide a transmission line interface switching method and a transmitter, wherein a type of a transmission line interface on an opposite transmitter side is automatically recognized, its own apparatus is switched according to the type of the transmission line interface, so as to correctly and quickly connect between the transmission apparatuses. SOLUTION: A selection section 1-4 selects one of transmission line optical interface sections 1-5 to 1-8 and the selected interface section is connected to the opposite transmitter via a transmission line. Looping back an optical signal from the opposite transmitter at an optical loopback section 1-3 as it is and its release are repeated at a particular time interval corresponding to the type of the transmission line optical interface, the optical signal from the opposite transmitter is received, whether or not a reception presence state and a reception absence state of the optical signal at a particular time interval are repeated is discriminated, the type of the transmission line optical interface used by the opposite transmitter is specified on the basis of the particular time interval, and the selection of the selection section 1-4 is switched to the transmission line optical interface of the specified type of the transmission line optical interface. COPYRIGHT: (C)2007,JPO&INPIT

Reliable bi-directional driving circuit for wide supply voltage and output range

Abstract: The present invention provides a bi-directional driving circuit for wide supply voltage and output range, which includes a power supply voltage, a bridge circuit containing a first switch, a second switch, a third switch and a fourth switch, in which the power supply voltage provides the power supply, the first, second, third and fourth switches are electrically connected to form two vertical arms respectively each having a first output terminal and a second output terminal, and the first output terminal and the second output terminal are electrically connected with a load; a first power controller containing an output terminal electrically connected with an input terminal of the first switch; a second power controller containing an output terminal electrically connected with an input terminal of the second switch; a third power controller containing an output terminal electrically connected with an input terminal of the third switch; a fourth power controller containing an output terminal electrically connected with an input terminal of the fourth switch; a first loopback network electrically connected with a differential amplifier and a second differential amplifier; a second loopback network containing a control voltage electrically connected therewith and electrically connected with the first differential amplifier, the second differential amplifier and the first output terminal of the bridge circuit; a third loopback network electrically connected with a third differential amplifier, a fourth differential amplifier, and the first output terminal and second output terminal of the bridge circuit; and a fourth loopback network electrically connected with the third differential amplifier and the fourth differential amplifier. A current that flows through the load is substantially independent of the power supply voltage and is proportional to the control voltage.

Method and apparatus for configuring a usb phy to loopback mode

Abstract: A method and system are disclosed for configuring a universal serial bus physical layer interface (USB PHY) to loopback mode without operational mode control signals supplied by an external tester. Loopback mode control signals are provided to the USB PHY from within the ASIC. Programmable storage elements in communication with control inputs of the USB PHY may receive the loopback mode control signals. A system includes a universal serial bus physical layer interface (USB PHY), programmable storage elements in communication with control inputs of the USB PHY, and a processor to set the programmable storage elements. The processor initiates the loopback mode of the USB PHY by sending the appropriate control signal sequence to the programmable storage elements. The processor may also enable the generation of hardware generated or programmed test data.

Inter-station test performance method applied to ring network system, and the ring network system

Abstract: PROBLEM TO BE SOLVED: To provide an inter-station test performance method and system applied to ring network system, capable of reducing the test time of an inter-station test and continuing the present operating state of all the stations at the execution of the inter-station test. SOLUTION: When an operating mode of a transmission station 1a is changed into an operating mode of the inter-station test, wherein a transmission station 1b acts as a slave station, the transmission station 1a takes measures that the transmission station 1a transmits a notice 10 of the execution of the inter-station test, to the transmission station 1b and receives the reception notice from the transmission station 1b to allow an adjoining inter-station test unperformance station 1f to perform loopback processing 12. The transmission station 1b, upon receiving the notice, transmits the reception notice to the transmission station 1a and takes measures of allowing an adjacent inter-station test unperformed station 1c to perform loopback processing 12. While the data links by loopback transmission of the inter-station test unperformance stations 1c, 1f, are being maintained, the transmission station 1a and the transmission station 1b perform the inter-station test between each other. COPYRIGHT: (C)2007,JPO&INPIT