Hewlett-packard Company

Juniper Networks, Inc.

3com Corporation

Cisco Technology, Inc.

David Lipschutz

John C Carney

Thomas Radogna

John A Flanders

Bernard Joseph Savord

Karl E Thiele

John Joseph Williams, Jr

Paul A Magnin

Thomas A Lemaire

Stephen L Van Seters

Thomas J Hunt

Steven C Leavitt

William D Townsend

Christopher P Lawler

David C Ready

Paul J Giacobbe

Leonard Schwartz

Shannon Q Hill

Robert Millard France

Thomas A Radogna

Stephen E Lincoln

George Azevedo

Optimizing a bitmap data tree and a corresponding lookup operation in the bit map data tree may be provided. A number of branches for each search node of a data tree may be counted. The data tree may comprise a plurality of search nodes. Then an optimum depth for the plurality of search nodes may be identified based on the number of branches in the data tree. Next, a hash node may be added to replace a search node of the data tree when a number of branches for the search node is greater than the identified optimum depth.

Methods and systems for data packet routing

A system receives a set of datagrams and forms frames based on the datagrams, where at least one of the frames includes data associated with multiple ones of the datagrams. The system writes the frames to memory to form superframes in the memory, where each of the superframes includes multiple ones of frames. The system reads the superframes from the memory, recreates the datagrams based on the superframes, and outputs the datagrams.

Scalable central memory switching fabric

A method may include determining a schedule of flush events for a queue and identifying whether the queue includes information associated with a partial data unit, the partial data unit being a data unit that is less than completely filled with data. The method may include identifying whether the queue should be flushed based on the schedule of flush events, and identifying that the queue includes the information associated with the partial data unit. The method may further include waiting for additional data to add to the queue, in response to identifying that the queue should not be flushed; and sending out the partial data unit, in response to identifying that the queue should be flushed.

Processing of partial frames and partial superframes

Quality of Service (&ldquo;QoS&rdquo;) variables for predetermined protocol Type data units are stored in a cache memory. For data units that are associated with a flow, thirteen bytes selected out of the Internet Protocol (&ldquo;IP&rdquo;) header are employed as at least a portion of a key to perform a cache lookup to obtain at least one Quality of Service variable from the cache. Both routing and QoS information may be stored in the cache for retrieval upon a single lookup operation.

Quality of service control mechanism and apparatus

A method and cache management for a bridge or bridge/router providing high-speed, flexible address cache management. The unit maintains a network address cache and an age table, searches the cache for layer 2 and layer 3 addresses from received frame headers, and returns address search results. The unit includes an interface permitting processor manipulation of the cache and age table, and supports a 4-way set associative cache to store the network addresses. A plurality of functions implemented in hardware enables software manipulation of the associated cache. Four cache operating modes are selectable. The unit can identify and select destination ports within a Load Balanced Port Group for frame forwarding. The unit utilizes Virtual LAN identification in conjunction with a MAC address for lookup in the cache. A cyclic redundancy code for each address to be looked up in the cache is used as an index into the cache. If a cache thrash rate exceeds a predetermined threshold, CRC table values can be rewritten. Four time-sliced cache lookup units are provided, each consisting of a cache lookup controller for comparing a received network address to an address retrieved from an identified cache set.

High speed cache management unit for use in a bridge/router

A phased array digital ultrasound beamformer for use with an ultrasound transducer array. The beamformer includes a processing channel for each element of the transducer array. Each processing channel includes a digitizing circuit for converting the received signal to digital samples and a time multiplexed digital delay circuit responsive to delay coefficients for delaying the digital samples by time multiplexed delays to produce delayed, time multiplexed samples for forming two or more receive beams. The ultrasound beamformer further includes a summing circuit for summing the delayed, time multiplexed digital samples from each processing channel to form a stream of time multiplexed output samples that is simultaneously representative of two or more receive beams. A coefficient generator supplies the delay coefficients to the time multiplexed delay circuit in each of the processing channels.

Time multiplexed digital ultrasound beamformer

A delay interpolator for use in each channel of a digital ultrasound beamformer includes an FIR digital filter that is responsive to delay control information for delaying digital samples of the received beam by different delays that are quantized in increments less than the sampling period and a control unit for supplying the delay control information to the FIR digital filter. In a preferred embodiment, all but one of the filter coefficients are of the form 1/2.sup.m, where m is an integer, and multiplication is implemented in the FIR digital filter by shifting bits of the data samples by m bit positions. The FIR digital filter preferably includes a gain correction multiplier for correcting the gain of the delayed digital samples. The FIR digital filter delay interpolator can utilize a pipeline structure for high speed operation. In addition, the FIR digital filter delay interpolator can be used in a time multiplexed beamformer to process several beams simultaneously.

Delay interpolator for digital phased array ultrasound beamformers

A method and apparatus for adaptively enhancing a scanned ultrasound image of a body portion having both areas of tissue and areas of blood pool. Clutter which appears in the blood pool areas is removed by processing the image signal to generate a mask signal, which signal is substantially present in areas of tissue to pass such areas and is substantially not present in areas of blood pool to block such areas. The image signal is modulasted with the mask signal, preferably on a pixel-by-pixel basis, to substantially remove the clutter.

Adaptive contrast enhancement for scanned ultrasonic image

This invention provides an improved circuit for dynamically controlling a predetermined characteristic of each input channel of a system having a plurality of input channels to achieve a desired characteristic profile with predetermined time variances in channel aperture size and/or focal point depth. More particularly, the invention dynamically controls the gain of each input channel to maintain a desired apodization profile. A plurality of basic time varying functions (basis functions) are generated, such functions being, for example, a constant, a ramp, a parabola an exponential or the like, and at least selected ones of the basis functions are combined by appropriately weighting the functions and adding the weighted functions to obtain a desired control signal. The control signal which has the desired dynamic gain characteristic for the given channel is then applied to control a gain-controllable amplifier for such channel. The number of combining elements may be reduced by providing such combining elements for only a selected number of spaced channels and by linearly interpolating the signals obtained from such combining elements for each pair of spaced channels to obtain control signals to control gain for channels between each pair of spaced channels. System gain may also be controled by a signal generated by combining at least selected ones of the basis functions through weighting and adding.

Dynamic control circuit for multichannel system

Apparatus for calculating the delay coefficients to be used for the transducer of a linear array at successive focal points along each radial line of a sector along which ultrasonic pulses are transmitted comprising a plurality of clocked accumulators connected in series, the accumulators being preloaded with appropriate combination of the coefficients of the successive terms of a series expressing an approximation of the formula, D=R-.sqroot.(X-Xo).sup.2 +Yo.sup.2 where R is the distance of a focal point from a given point in the sector, X is the number of the accumulator from the origin and Xo, Yo are the coordinates of the focal point.

Delay coefficient generator for accumulators

Ultrasonic apparatus for representing the velocities of flow of fluid occurring with an image plane by changing the hue and intensity of the colors with changes in flow rate.

Flow map apparatus

Estimates of the average velocity and turbulence of blood flow are determined by weighting the instantaneous frequencies of a returning Doppler signal. The weighting can be chosen so that the estimates are optimized. The weighting can be chosen so as to duplicate the algorithm of other ultrasound flow imaging systems.

Growing community of inventors

Lexington, MA, United States of America

David Lipschutz