Abstract: A method (50) of communicating bit groups between a first DSL modem (M14) and a second DSL modem (M12). The method receives (56) at the first DSL modem a plurality of bit groups (FF1-FF500) from the second DSL modem. Each of the plurality of bit groups comprises a plurality of bit sub-groups (W1-W12), and each of the plurality of bit sub-groups has an order of location. For each of the plurality of bit groups, the method determines (58) whether bits of at least one sub-group having a common order of location comprise at least one erroneous bit. In response to this determination, the method stores (62, 64) in the first DSL modem a record (InMaskBuff) of whether the at least one sub-group having the common order of location comprises at least one erroneous bit. From this record, various other steps (72) may be taken in the preferred embodiment, including suppressing (82) the at least one sub-group from communicating valid information from the second DSL modem to the first DSL modem.

Abstract: A method of modem communications between first and second modems (10, 20k) over a communications facility (TWP). The method operates the first modem (20k) to issue communications to the second modem (10) over the communications facility. These communications comprise a plurality of subchannel signals (n). The method also operates the second modem to perform various steps. In one of these steps, the second modem converts (33) the communications from time domain communications to frequency domain communications, where the frequency domain communications signals comprise a plurality of subchannel signals. Each of these plurality of subchannel signals comprises an amplitude portion and a phase portion. In another of these steps, the second modem equalizes (36) the amplitude portion of each of the plurality of subchannel signals using fixed gain factors (GE(n))corresponding to each of the plurality of subchannel signals.

Abstract: A modem (55) including receive circuitry (30) implemented by way of a digital signal processor (32, 32′) is disclosed. The receive circuitry (30) operates according to a receive clock (CLKr) that is based upon the output of a free run oscillator (50). An incoming frequency multiplexed signal (f(t)) is sampled by an analog-to-digital converter (31) and demodulated by way of a Fast Fourier Transform function (36). After such demodulation, a phase rotation function (40) applies a phase shift to the demodulated signal corresponding to an estimated phase offset (&tgr;) between the receive clock (CLKr) and a pilot signal (P) transmitted by the transmitting modem; a finite impulse response filter function (42) applies a digital filter to the demodulated signal to correct for phase error based upon an estimated frequency offset (&Dgr;).

Abstract: The present invention provides a method and system of transceiving a data signal in a HomePNA type network. The transceiver enables digital signal processing of the data signal compliant with the HomePNA 10M8 specification in an Open System Interconnection type network over a shared medium such as a client's home phoneline (1206). The transceiver can be implemented in each station (1202) of the HomePNA single-segment network (1204) in which each station is logically connected to the same shared channel on the phonewire (1206). The transceiver enables transmission of the data signal in burst on the shared channel while complying with the spectral mask (310), temporal mask (330) and other electrical requirements as specified in the HomePNA 10M8 technology.

Abstract: An equalization technique for an ADSL data communications system is disclosed. The effective channel overall response is made a window of length I equal to the length of the cyclic prefix. The response energy output of filtering is monitored against a preset threshold value to adaptively position the window.

Abstract: An equalization technique for an ADSL data communications system is disclosed. The effective channel overall response is made a window of length I equal to the length of the cyclic prefix. The response energy output of filtering is monitored against a preset threshold value to adaptively position the window.

Abstract: A method of initializing the operation of a remote modem (10) and central office modem (20k) for asymmetric subscriber line modem communications over a twisted pair wire facility (TWP), using discrete multi-tone technology, is disclosed. The initialization process begins with the remote modem (10) issuing an initialization request, in response to which the central office modem (20k) issues an acknowledgment. The remote modem (10) includes a low-cost analog filter (21) for separating upstream communication echoes from downstream data. This analog filter (21) increases the duration of impulse response over the channel, and thus requires time-domain equalization (TEQ) process (31) performed by the remote modem (10) to filter relatively long circular prefixes, so that intersymbol interference is eliminated.

Abstract: A method to estimate the bit loading on each tone of a DMT digital subscriber loop system is disclosed. A generic bit-mapping table is given for different sizes of constellations to save memory space.

Abstract: A clipping protection scheme for a discrete multi-tone (DMT) digital subscriber loop modem telecommunications system determines the occurrence of clipping by checking the overflow bits in the IFFT status register. The transmitter then sends a predefined data stream to notify the receiver of the event, and then breaks the data into two frames for consecutive transmission to the receiver.

Abstract: An echo cancellation scheme for DMT MDSL digital subscriber loop telecommunications data transfer is disclosed. The echoed data stream frame is aligned with the incoming data stream frame. The time domain equalizer trims the lengths of both the DSL channel and echo channel within the length of the cyclic prefix, so that the time domain convolution for synthesizing the echo is accomplished within the FFT process, enabling the echo to be subtracted in the frequency domain.

Abstract: A modem communication system with receiving and transmission paths includes a direct equalizer system having an adaptive filter (1532) in the transmission path to compensate for frequency distortion of the communication channel. The transmitter filter coefficients are adapted by a filter coefficient calculator (1528), under control of a data detector (1526) which detects incoming data in the receiving path. A switch (1534) is controlled by status of a transmit output data buffer to multiplex either the training sequence or output data into the transmission path. When the buffer is idle, the training sequence generator (1540) is linked to a digital-to-analog (D/A) converter (1536) and line driver (1538). The receiving path includes an isolation switch (1520), a receiver amplifier (1522) and a slicer (1524). The receiver correlates the received training sequence with a known training sequence and updates the equalizer filter coefficients using an adaptation algorithm, such as a least mean squared algorithm.

Abstract: A modem selectively operated in the voice and higher frequency band which supports multiple line codes. The modem uses a digital signal processor so that different existing ADSL line codes can be implemented on the same hardware platform. The modem negotiates in real-time for a desired line transmission rate to accommodate line condition and service-cost requirement. The line code and rate negotiation process may be implemented at the beginning of each communication session through the exchange of tones between the modems. A four-step MDSL modem initialization process is provided for line code and rate compatibility. A synchronization startup procedure for DMT based MDSL modems is provided. The handshake protocol and receiver algorithm allow reliable standard telephone twisted-pair wire. The algorithm makes use of a short length sequence to train a synchronizing equalizer at the receiver. After training to this sequence, a matched filter or correlator is used to detect the inverted sync sequence.

Abstract: A modem operating selectively in the voice frequency and higher frequency bands which supports multiple line codes. A DSP is used to implement different existing ADSL line codes on the same hardware platform. The modem negotiates in real time for a desired line transmission rate to accommodate line condition and service cost requirements which may be implemented at the beginning of each communication session by exchange of tones between modems. A four step MDSL modem initialization process provides line code and rate compatibility. The handshake protocol and receiver algorithm for CAP based MDSL modems allows reliable modem synchronization over severely amplitude distorted channels and makes use of a short length sequence to train a synchronizing equalizer at the receiver. The algorithm and corresponding training sequence to train the transmitter filter are provided. After training to this sequence, a matched filter or correlator detects the inverted sync sequence.

Abstract: A process for fabricating Ultra Large Scale Integrated (ULSI) circuits in Silicon On Insulator (SOI) technology in which the device structures, which can be bipolar, FET, or a combination, are formed in vertical silicon sidewalls having insulation under and in back thereof so as to create SKI device structures. The silicon sidewall device SOI structures, when fabricated, take the form of cells with each cell having a plurality of either bipolar devices, FET devices, or a combination of these devices, such as collectors, emitters, bases, sources, drains, and gates interconnected within the planes of the regions of the devices in the cells and can be interconnected within the planes of the regions of devices in adjacent cells. Further, the interconnections to adjacent cells can be made from the back of the silicon sidewalls.

Abstract: A method and system for controlling reheater steam temperature is disclosed. The method can be carried out by selectively adjusting the flow of superheated steam into a superheater positioned between two reheater sections in the convection pass of a carbonaceous fuel boiler system.

Abstract: A method and system for recycling a sulfur sorbent present in the combustion residue of a circulating, fluidized bed, fossil-fuel combustor is disclosed. The method can comprise the steps of, adding water to the combustion residue, classifying the combustion residue into a fuel ash portion and a hydrated sorbent portion, and returning the hydrated sorbent portion to the circulating, fluidized bed, fossil-fuel combustor.

Abstract: A biased air distribution grid is used to promote solids entrainment and dense bed internal mixing for the bed material of a fluidized bed reactor. The air distribution grid distributes air at a high velocity zone having a velocity ranging from 11 to 50 feet per second and a low velocity zone having a velocity ranging from 3 to 10 feet per second. The high velocity zone and the low velocity zone provide an improved lateral mixing for the reactor.

Abstract: A cyclone separator for a solids-laden process gas from a reactor also provides a pressure seal for the reactor. The cyclone includes a main housing with a longitudinal axis. The housing is made of a membrane wall construction having a plurality of tubes arranged around the axis and encased within membrane wall panels. A portion of the tubes are bent outwardly to form an inlet which communicates with the main housing for receiving the solids-laden process gas from the boiler. Solids are separated from the solids-laden process gas as they swirl together in the main housing of the cyclone separator. A partition wall is disposed at the lower section of the main housing around the longitudinal axis for defining an outer chamber and an inner chamber adjacent to the outer chamber. Gas is provided to the outer and inner chambers for creating fluidized beds of the solids in the outer and inner chambers. Solids are passed from the inner chamber to the outer chamber through an underflow port in the partition wall.