Abstract: A USB function device (14) for coupling to a USB host (12). The USB function device (14), comprises circuitry (32) for providing a capability to the USB host, where the circuitry for the capability comprises an address space. The USB function device further comprises a USB interface circuit (136) coupled between the USB host (12) and the circuitry (32) for providing a capability to the USB host. The USB interface circuit comprises a memory area (106) comprising a code overlay endpoint (1061) accessible to the USB host for writing two or more code blocks to the code overlay endpoint. The USB interface circuit further comprises circuitry (150-163) for communicating a first of the code blocks from the code overlay endpoint to the address space and for subsequently communicating a second of the code blocks from the code overlay endpoint to the address space.

Abstract: An integrated circuit (10) comprising combinational circuitry (13). The integrated circuit further comprises a plurality of scan channels (SC1 through SC4). Each of the plurality of scan channels comprises a number of scan elements (EC11 through EC45). For any of the plurality of scan channels having a number of scan elements greater than one element, the scan channel comprises a first element in the scan channel and a last element in the scan channel. For any of the plurality of scan channels having a number of scan elements equal to one element, the one element is both a first element and a last element in the scan channel. Further, selected ones of the scan elements are coupled to affect operation of the combinational circuitry. The integrated circuit further comprises circuitry (24) for coupling a predetermined pattern into the first element of each of the plurality of scan channels and circuitry (26) for detecting the predetermined pattern in the last element of each of the plurality scan channels.

Abstract: The present invention is a method of reducing latency in transmitting frames of data in a shared access media environment whereby the preamble of the next frame to be transmitted is transmitted while the data portion of the next frame to be transmitted is being retrieved. In another aspect, the early transmission of the preamble of the next frame is started no later than the time it normally takes to fetch and prepare the next frame for transmission less the time it takes to transmit the preamble.

Abstract: A method for symbol detection using a decision feedback equalizer loop is provided comprising the steps of generating a delay-less symbol estimate from data redundancy in a received signal, and employing said delay-less symbol estimate in said decision feedback equalizer (DFE) loop as input to the feedback section of the DFE and/or to update equalizer parameters. A receiver for digital signals is also provided. Other systems, apparatus and methods are also disclosed.

Abstract: This invention is particularly useful as a system for digital communications over channels that suffer from impulse noise, and particularly over return cable TV channels, downstream cable TV channels, and digital subscriber loops (DSL) channels for high speed communications over twisted pair copper lines.

Abstract: In a cable television (CATV) data communication network, channel throughput and communications robustness are increased in a manner that improves speed of data transmission while maintaining compatibility with existing specifications and equipment. Enhanced throughput can be realized using the return channel of the CATV network. Alternatively, data retransmission and/or diversity techniques can be used to improve throughput.

Abstract: A data communication system that provides different types of service (e.g., telephone services and high-speed data transmission services) to a remote site even when the remote site lacks a splitter is disclosed. A central site (e.g., central office) is able to communicate with at least two different types of remote sites. One type of remote site includes a full splitter (i.e., both low-pass and high-pass filters), and the other type of remote site has only a partial splitter (i.e., includes high-pass filter but lacks a low-pass filter). Although conventionally the transceivers (e.g., ADSL transceivers) at these remote sites would be of the same design and use the same modulation technique for upstream as for downstream transmissions, here the remote site that lacks a low-pass filter (i.e., partial splitter type remote site) uses a different modulation technique for upstream transmissions.

Abstract: The operation of a line card in the local exchange of a point-to-point switched telephone network is modified to increase the data rate of voiceband modem transmission by increasing the sampling rate and providing controlled intersymbol interference using partial response techniques.

Abstract: A collision-based multi-access system is described which is capable of recovering collisions by means of jointly detecting the mutually interfering signals, followed by re-transmission of functions of portions of some of the colliding signals. This system reduces the amount of required re-transmission of all of the colliding signals, decreasing the amount of re-transmission in the system, increasing the system throughput. The system is also applicable to non-colliding communications systems to correct interference due to noise.

Abstract: A priority encoder circuit (10, 60) is provided. The priority encoder circuit (10, 60) includes a plurality of inputs (38, 90) and outputs (40, 92). The number of inputs (38, 90) equals the number of outputs (40, 92), and each input (38, 90) corresponds to one output. Each input (38, 90) receives a signal that indicates whether the input (38, 90) has been selected. The priority encoder circuit (10, 60) also includes circuitry (50, 100) that generates a signal at the output (40, 92) corresponding to the input (38, 90) having the highest priority that receives the selection signal.

Abstract: A packet switch (26) has N digital input ports (28) each of bandwidth B for receiving data cells including destination addresses for determining output ports, a shared input cache (32), N memory modules (36) of bandwidth N.times.B for buffering, a switch fabric (38), and N digital output ports (40). A digital multiplexer (30) receives each data cell from the input ports (28) and writes it to the shared input cache (32) together with a corresponding port queue number, queue position, and memory module number in response to its destination address so that (1) cells having the same queue number are cyclically assigned to different memory modules (36) and (2) cells having the same queue position are cyclically assigned to different memory modules (36). A digital demultiplexer (34) reads each data cell from the shared input cache (32) and writes it to one of the N memory modules (36) according to its assigned memory module number and queue position.

Abstract: A self-testing smart memory (28) is provided in which memory test circuitry (46) within the smart memory (28) writes a pattern to a data RAM (32) and a broadcast RAM (34) and then reads the data RAM (32) and the broadcast RAM (34) to determine if any failures exist within the memory locations. Furthermore, a data path tester (50) determines the functionality of a data path (30) within smart memory (28).

Abstract: The present invention is an apparatus and method for blind automatic gain control in a digital communications device. The present invention includes a maximum error detector (MED) (142) which includes a gain error evaluator (GEE) (144) and a maximum value detector (MVD) (146). Also included is a decision gain adjustor (DGA) (148) which includes a gain value controller (GVD) (150) and an initial value buffer (IVB) (152). The GEE (144) is operable to generate a gain error signal in accordance with an input baseband signal (x) and a sliced version of the input baseband signal (x'). The MVD (146) is operable to generate a renew signal in accordance with the sliced version of the input baseband signal (x') and a first predetermined reference value. The GVD (150) is operable to converge the gain error signal (.DELTA.x) in a first state using a first convergence technique and to converge the resultant signal in a second state using a second convergence technique.

Abstract: A method and apparatus for supporting multiple bit allocations in a multicarrier modulation system are disclosed. Hence, symbols being transmitted or received can make use of different bit allocations. By supporting the multiple bit allocations, the multicarrier modulation system is able to support bit allocation on a superframe basis. Also disclosed are techniques for selection and alignment of superframe formats to improve system performance.

Abstract: A network hub and Asynchronous Transfer Mode (ATM) translator system (5) for use in a Local Area Network (LAN)-based communications system is disclosed. The network hub and ATM translator system (5) includes a host controller (10) that serves as the LAN hub, and which interfaces with a translator card (15) which includes a segmentation and reassembly device (12) in connection with SONET receive/transmit circuitry (20) that communicates with a transceiver (22) to transmit and receive ATM packet cells over a communications facility (FO). The translator card (15) also includes a scheduler (14) that includes a heap sort state machine (36) which maintains a sorted list of entries, in a heap fashion, in on-chip parameter memory (44) and off-chip parameter memory (18). The entries include, for each ATM channel, a channel identifier and a timestamp that indicates the time at which the next cell for the channel will be due for transmission. A due comparator (40) compares the timestamp of the root value in the heap (i.

Abstract: An infinite impulse response (IIR) digital filter and method of performing the same is disclosed. The digital filter may be realized by way of a programmable logic device, such as a digital signal processor (75), or alternatively by way of dedicated logic including adders (44, 48, 50, 54, 58, 62, 66, 70, 72) and shifters (46, 52, 56, 60, 64). In either case, addition operations (34) are interleaved among first and second output sample values (y.sub.n-1, y.sub.n-2), so that the resulting addition (30; 72; 215; 320) may be carried out with adder circuitry of the same precision as the signal input (x.sub.n) and signal output (y.sub.n). Carry control circuitry (76, 78, 80, 82, 84, 88; 217; 317) is provided to efficiently incorporate magnitude truncation quantization.

Abstract: A method for establishing a correspondence between chemical use and the process where use occurs. The process is assigned a process identification number (PIN). After chemicals have been assigned into an inventory, the chemicals are assigned to the process and a report is generated reporting the chemical use corresponding to the process.

Abstract: A method of communicating bit groups between a first DSL modem and a second DSL modem. The method receives at the first DSL modem a first bit group from the second DSL modem. The first bit group comprises a flow control bit in a fixed location within the first bit group. In response to the flow control bit being in a first state, the method transmits a second bit group from the first DSL modem to the second DSL modem, wherein the second bit group consists of filler data. In response to the flow control bit being in a second state, the method transmits a third bit group from the first DSL modem to the second DSL modem, wherein the third bit group comprises data other than filler data.

Abstract: To overcome the problem of poor representation of the background noise, the present invention includes a noise parameter generator (40) which uses a weighted average of auto-correlation values of the input signal generated during the noise-analysis phase. The weighting function gives less weight to the auto-correlations during the first few frames (as they may contain speech) and more weight to frames towards the end of this phase. Also included, to overcome the bursty nature of comfort noise, is a comfort noise generator (50) which gradually changes the nature of the signal from speech to pseudo-random noise after the speech-burst. The comfort noise generator (50) of the present invention excites the auto-regressive filter corresponding to the noise model with a weighted combination of the past excitation and pseudo-random noise.

Abstract: The present invention is a method and system which determine signal probability and transfer probability for each node in a netlist describing an electrical circuit; determine, using the signal probability and transfer probability, a fault detection probability for each node; and, using the fault detection probabilities, determine overall fault coverage of the electrical circuit described in the netlist. The method and system of the present invention then, using the fault coverage data, heuristically determine a set of testpoints to be inserted into the netlist which increase the overall fault coverage of the electrical circuit above a predetermined value.