Abstract: A header-information adding unit adds a device ID for identifying a device at a sending node and a device ID for identifying a device at a receiving node to a header of a packet sent by the sending node. The packet is transmitted to a data-format converting device by a packet transmitting unit. In the data-format converting device, the packet is received by a packet receiving unit, and is sent to a unique-information detecting unit. The unique-information detecting unit detects the device IDs from the header of the packet, and sends them to a data-format converting unit with the packet data. The data-format converting unit determines the data formats used by the sending node and the receiving node based on the detected device IDs, and converts the data format of the packet sent by the sending node into the data format of by the receiving node.

Abstract: Apparatus, and an associated method, for space-time encoding data to be communicated upon a communication channel susceptible to fading. Multi-rate data services can be effectuated through appropriate selection of the code rate by which data is encoded. And, the coding of space-time encoded data is facilitated as different permutations of coded data symbols are separate transmitted upon separate communication paths.

Abstract: In a discrete tone system, a base station receives a transmission burst from a remote unit being installed that includes delay compensation pilot tones that are uniformly spread throughout the transmission bandwidth. The arrival time transmission burst is not synchronized with the other remote units transmitting to the base station. The base station measures the phase delay of each tone and calculates the delay of the remote unit from the slope of the line of phase angle versus tone frequency. The base station transmits a signal to the remote unit that includes the magnitude and direction of the delay, which allows the remote unit to adapt the timing of its transmission to be synchronized with the other remote units.

Abstract: A method and circuit for achieving minimum latency data transfer between two mesochronous (same frequency, different phase) clock domains is disclosed. This circuit supports arbitrary phase relationships between two clock domains and is tolerant of temperature and voltage shifts after initialization while maintaining the same output data latency. In one embodiment, this circuit is used on a bus-system to re-time data from receive-domain, clocks to transmit-domain clocks. In such a system the phase relationships between these two clocks is set by the device bus location and thus is not precisely known. By supporting arbitrary phase resynchronization, this disclosure allows for theoretically infinite bus-length and thus no limitation on device count, as well as arbitrary placement of devices along the bus. This ultimately allows support of multiple latency-domains for very long buses.

Abstract: A procedure for determining active code sequences of a plurality of overlaid code sequences (c&agr;(&ngr;)·g&agr;), wherein the active code sequences have a greater gain factor(g&agr;) than the inactive code sequences, includes: (1) formation of a cost function(L) dependent upon unknown estimated values({tilde over (g)}&agr;, ĝ&agr;) of the gain factors (g&agr;) of composite code sequences(c&agr;(&ngr;)·g&agr;), (2) partial differentiation of the cost function (L) in accord with the unknown estimated values({tilde over (g)}&agr;ĝ&agr;) of the gain factors(g&agr;), (3) formation of an equation system from the presupposition that all partial differentials of the cost function (L) are zero and a minimum of the cost function (L) is present, (4) determination of the estimated values ({tilde over (g)}, ĝ&agr;) of the gain factors (g&agr;) by solving the equation system, and (5) determining that an active code sequence exists, if the estimated values({tilde over (g)}&agr;, ĝ&agr

Abstract: A time division multiplex switching apparatus is provided for switching channels from any number of input data streams, each of which may have any of a plurality of data rates, to any of a plurality of output data streams, each of which may likewise have any one of a plurality of data rates. An input block 1 comprises a respective input channel for each input stream. Each channel has a variable delay circuit. The outputs of the channels are supplied to a buffer memory 3 which stores data from the input channels in a first order and reads out the data in a second order according to the channel connections required. A controller 2 controls the variable delay circuits 12-14 independently of each other so as to align the data streams from the input channels irrespective of the input stream data rates. For example, the streams may be aligned such that the zeroth channel of a predetermined frame in the input streams appear consecutively at the outputs of the input channels.

Abstract: The present invention relates to a multiplexing apparatus, a receiving apparatus, and a method of multiplex transmission. Specifically, a multiplexing apparatus which multiplexes a plurality of encoded data streams adds arrival time T1 as temporal information indicative of timing for suppling the encoded data streams to a plurality of decoding units of a receiver to a time-division-multiplexed data stream. The receiver decodes the encoded data streams on the basis of the arrival time T1. So, even though the transmission bands allocated to the respective data streams are varied, synchronization between original data streams and decoded data streams is secured without deleting part of information of the original data streams.

Abstract: An architecture for providing high-speed access over frequency-division multiplexed (FDM) channels allows transmission of ethernet frames and/or other data across a cable transmission network or other form of FDM transport. The architecture involves downstream and upstream FDM multiplexing techniques to allow contemporaneous, parallel communications across a plurality of frequency channels. Also, the modulation indices of various upstream frequency channels may be different, but a plurality of upstream channels may be used to carry a single data flow generally in parallel. The upstream data flow is fragmented into blocks and formed into superframes to allow transmission over at least one upstream frequency channel. When a plurality of upstream frequency channels are utilized, the superframes facilitate the possibility of having different modulation indices on the plurality of frequency channels.

Abstract: There is provided a transmission device capable of efficiently synchronous multiplexing control for downsizing and reduction in power consumption. A count control part performs a channel management control on the basis of specific information on a cross-connect basis by commonly using a count control of channels of a high-bit-rate multiplexing unit signal and those of a low-bit-rate multiplexing unit signal. A head position detecting part detects a head position of path information based on a pointer value. A clock exchange memory part performs clock exchange with respect to valid path information indicated by the head position. A write counter generates a write count value, and a read counter generates a read count value. A pointer adding part adds a pointer to the valid path information read. A cross-connect circuit uses a two-plane memory, and cross-connects a signal with the pointer being replaced by memory reading based on memory switch information.

Abstract: A method and system are disclosed for synthesizing an electric field. In accordance with exemplary embodiments of the present invention, an electric field that changes across a distance in space is synthesized by applying voltage levels at several locations independently of one another. The independence in voltage levels allows the electric field that is synthesized to be made periodic or aperiodic. Such a synthesized electric field can be changed at any time for use in, for example, a tunable laser. According to an exemplary embodiment, the electric field is used to change the refractive index of an electro-optic substance in an optical filter. Such an optical filter can be used as part of, for example, a wavelength agile laser, an optical add drop multiplexer, an optical switch, or the like. Such an optical filter can also be used for dynamic power balancing, dynamic gain equalization, or the like.

Abstract: A cooling block 17 has three water channels 21 formed so as to be located near an LD device 18 fixed to a side surface 17c, each water channel 21 having a water channel sectional shape like an elongated hole, and being inclined relative to the side surface 17c. Heat generated by the LD device 18 is eliminated by cooling water flowing through the water channels 21. The water channel sectional area of an inlet manifold water channel is rendered not less than twice the water channel sectional area of the cooling block water channel. Irregularities are formed on the inner surface of each of the cooling block water channels. Further, an inlet portion of the cooling block water channel is chamfered or given a curvature.

Abstract: A laser support structure and method of mounting a laser in a module. The laser support structure is used in a laser module to support a laser in alignment with an optical fiber. The support structure comprises a frame having a base portion, and a mounting portion opposed to the base portion with a space therebetween. A dielectric layer to which the laser may be attached is suspended from the mounting portion and extends partially into the space between the mounting portion and the base portion. As the dielectric layer expands or contracts, it does so within the space between the mounting portion and the base portion with minimal displacement of the laser.

Abstract: A semiconductor laser device comprising a mount substrate, a semiconductor laser element, and a total reflection mirror. The substrate includes an n-type Si substrate, an i-type Si layer deposited on a part of the Si substrate, and a p-type Si layer deposited on the Si layer. The Si substrate and Si layers constitute a pin photodiode. A part of the sides of the Si layers is a sloping surface. The laser element is mounted on the substrate and has a light-emitting surface opposing the sloping surface. The mirror is provided on a part of the sloping surface. It reflects and outputs a central part of a light beam emitted from the laser element. It guides the remaining part of the light beam to the photodiode.

Abstract: The object of the present invention is to provide an optical module for the WDM communication system, in which the oscillation wavelength is on the grid of the WDM regulation, moreover the optical output power and the oscillation wavelength can be controlled independently. The present module comprises a semiconductor light-emitting device, a wedge shaped Ethalon device and two light-receiving devices. The Ethalon contains a first portion, on which the anti-reflection films are coated, and a second portion. One of the receiving devices detects light transmitted through the first portion of the Ethalon, while the other device detects light through the second portion. Signal from the former device controls the output power of the light-emitting device, while the signal from the latter receiving device controls the oscillation wavelength of the laser.

Abstract: A device for producing laser radiation, the device comprising: an elongate sample of a quasi-three-level laser material; a source of pumping radiation; and a concentrator configured such that at least some of the pumping radiation emitted by the source of pumping radiation is concentrated by the concentrator and subsequently enters the sample through a side surface thereof.

Abstract: A surface-emission laser diode includes a distributed Bragg reflector tuned to wavelength of 1.1 &mgr;m or longer, wherein the distributed Bragg reflector includes an alternate repetition of a low-refractive index layer and a high-refractive index layer, with a heterospike buffer layer having an intermediate refractive index interposed therebetween with a thickness in the range of 5-50 nm.

Abstract: In a semiconductor laser device provided with a semiconductor laser element for outputting a laser beam having a plurality of oscillation longitudinal modes at a stimulated Brillouin scattering threshold or less, a submount formed by diamond and set between the semiconductor laser element and a carrier each configured to enable a highly efficient transfer of heat between the semiconductor laser device components.

Abstract: A vertical-cavity surface-emitting laser structure is provided. The device comprises a structure which consists of: a substrate; a multi-layered structure stacked over the substrate, which consists of a bottom distributed Bragg reflector, a bottom cladding or spacer layer, a light-emitting active layer, a top cladding or spacer layer, a top distributed Bragg reflector (DBR). An annular disordered region (or disordered absorber) with an aperture is formed in a part of top or bottom DBR for transverse modes control; an active region aligned with the aperture of the annular disordered region is formed on the light-emitting active layer; and a p-electrode and an n-electrode are formed on a p-type and an n-type layers respectively. The device structure is to provide a vertical-cavity surface-emitting laser that can operate in a stable single-mode with a sufficient output power and high yield production.

Abstract: A self aligned, index-guided, buried heterostructure AlGaInN laser diode provides improved mode stability and low threshold current when compared to conventional ridge waveguide structures. A short period superlattice is used to allow adequate cladding layer thickness for confinement without cracking. The intensity of the light lost due to leakage is reduced by about 2 orders of magnitude with an accompanying improvement in the far-field radiation pattern when compared to conventional structures. The comparatively large p-contact area allowed by the self-aligned architecture contributes to a lower diode voltage and less heat during continuous wave operation of the laser diode.

Abstract: An index-guided buried heterostructure AlGaInN laser diode provides improved mode stability and low threshold current when compared to conventional ridge waveguide structures. A short period superlattice is used to allow adequate cladding layer thickness for confinement without cracking. The intensity of the light lost due to leakage is reduced by about 2 orders of magnitude with an accompanying improvement in the far-field radiation pattern when compared to conventional structures.

Abstract: Bypassing the terminal current through a multiplicity of active regions contained within the same optical cavity, easily fabricated diode lasers with external differential efficiencies greater than unity are created. Such multiple-active-region lasers can enable optical links with net electrical-to-electrical signal gain as well as facilitate impedance matching at the source. These devices can also be used within tunable laser structures, vertical laser structures or other complex laser cavity structures to provide low-cost monolithic devices with unique, desirable capabilities. When the terminal current is supplied by an integrated photodetector, low-noise optical-optical signal gain can be provided in a single monolithic semiconductor component formed by a compatible materials technology.

Abstract: A laser diode pump includes a plurality of laser diodes each capable of generating a lasing wavelength. The laser diode pump further includes at least one wavelength combiner operable to combine the plurality of lasing wavelengths generated by the plurality of laser diodes into a multiple wavelength pump signal. In one particular embodiment, at least two of the plurality of lasing wavelengths generated by the plurality of laser diodes comprise a wavelength between 1270 nm and 1350 nm.

Abstract: Normal incidence stack architecture coupled with the development of diode array pumping enables the power/energy per disk to be increased, a reduction in beam distortions by orders of magnitude, a beam propagation no longer restricted to only one direction of polarization, and the laser becomes so much more amendable to robust packaging.

Abstract: The present invention has applications in high-bandwidth communications systems and other applications that utilize modulated optical energy. In one aspect of the invention, a short cavity diode-pumped laser generates optical energy that may be modulated over a wide range of frequencies. In one embodiment, the short cavity diode-pumped laser may be modulated at rates up to 15 GHz. The short cavity diode-pumped laser may include a laser diode modulator and a laser coupled to the laser diode modulator having a cavity lifetime of less than about 100 picoseconds.

Abstract: A short-wavelength vertical cavity surface emitting laser (VCSEL) is flip-chip bonded to a long-wavelength VCSEL. The short-wavelength VCSEL is used to optically-pump the long-wavelength VCSEL. Certain embodiments of the invention can serve as optical sources for optical fiber communication systems. Methods also are provided.

Abstract: A multiple reflectivity band reflector (MRBR) includes a stack of dielectric layers, arranged so that the reflector has a reflectivity profile comprising a plurality of reflectivity bands, e.g. at least first and second wavelength bands with reflectivity above a lasing threshold reflectivity, separated by a third wavelength band between the first and second wavelength bands having reflectivity below the lasing threshold reflectivity. A laser having at least a first mirror and an MRBR as the second mirror has a laser cavity, at least a portion of which is defined by the first mirror and the MRBR. An active region located within the laser cavity contains a material that is capable of stimulated emission at one or more wavelengths in the first and second wavelength bands. The gain spectrum of the laser is adjusted to select one of the first and second wavelength bands, thereby providing for lasing at a wavelength within the selected wavelength band. The laser may be, e.g.

Abstract: A laser apparatus has a first mirror, a second mirror, at least a portion of which is defined by the first and second mirrors. The laser has an active region located in the laser cavity, which is capable of stimulated emission at one or more wavelengths of light. The second mirror comprises a plurality of dielectric layers arranged in parallel and having a reflectivity band with a peak reflectivity at a peak wavelength, said reflectivity band having a width of less than 1 nm at a reflectivity of 3% less than the peak reflectivity. The laser apparatus may be a tunable laser apparatus in which the peak wavelength of the reflectivity band is adjusted, thereby adjusting the lasing wavelength of the laser. The reflectivity band may be a lasing threshold reflectivity band over which the reflectivity of the second mirror is greater than a lasing threshold reflectivity which is sufficient to permit lasing.

Abstract: Methods of and systems for illuminating objects using planar laser illumination beams having substantially-planar spatial distribution characteristics that extend through the field of view (FOV) of image formation and detection modules employed in such systems. Each planar laser illumination beam is produced from a planar laser illumination beam array (PLIA) comprising an plurality of planar laser illumination modules (PLIMs). Each PLIM comprises a visible laser diode (VLD, a focusing lens, and a cylindrical optical element arranged therewith. The individual planar laser illumination beam components produced from each PLIM are optically combined to produce a composite substantially planar laser illumination beam having substantially uniform power density characteristics over the entire spatial extend thereof and thus the working range of the system.

Abstract: A metallurgical furnace, which includes a furnace shell, an exhaust system, and a gas cleaning system, further includes a plurality of improved pipes and fume ducts throughout to increase operational life and productivity. The pipes and fumes ducts are comprised of an aluminum-bronze alloy which provides enhanced properties over prior art materials including thermal conductivity, modulous of elasticity and hardness. The use of the alloy also minimizes maintenance requirements of the pipes and fume ducts, thereby extending their operational life. In operation, gases formed from smelting or refining are evacuated from the furnace shell through the exhaust system into the gas cleaning system. The gases, as well as the system, are water cooled by way of the plurality of pipes displaced throughout.

Abstract: In order to precisely analyze thermal deformation of a substance which thermally shrinks over time, the amount of deformation of a substance is determined by separate steps of calculation of elasto-plastic deformation during temperature increase (step S12); calculation of creep deformation from the time when the temperature increase is completed till the time when the temperature decrease is started (step S14); and calculation of elasto-plastic deformation during the temperature decrease (step S16). When calculating the creep deformation, it is assumed that deformation due to the thermal shrinkage of the substance over time occurs simultaneous with the creep deformation, and strain rate is calculated as the time derivative of the total strain which is the sum of creep strain and the strain produced by thermal shrinkage. The creep deformation is then calculated by integrating the strain rate over the time from when the temperature increase is completed until the time when the temperature decrease is started.

Abstract: A transducer assembly for measurement of downhole temperature and (if required) pressure includes a crystal resonator responsive to temperature and a pair of temperature sensors such as thermocouples or RTDs. One sensor is located with the crystal resonator and the other is exposed to external conditions such as those adjacent the pressure resonator. Thus, the sensors provide a correction signal for the resonator and allow improvement in the transient response of the transducer. A feedback circuit for correcting the resonator output is also disclosed.

Abstract: An arrangement for measuring the temperature of an electronic circuit, the arrangement comprising

Abstract: Methods and apparatus for use in generating data sequences for direct sequence spread spectrum (DSSS) communications are described. One exemplary method includes the steps of serially generating a pseudo random noise (PN) sequence by, for each count value i of a plurality of count values, retrieving from memory a bit of the PN sequence corresponding to the (i)th position in the PN sequence. The exemplary method includes the further steps of serially generating a Gold code sequence by, for each count value i of the plurality of count values, retrieving from memory a bit of the PN sequence corresponding to the (i+n)th position in the PN sequence, retrieving from memory a bit of the PN sequence corresponding to the (q*i)th position in the PN sequence, and adding the bit corresponding to the (i+n)th position with the bit corresponding to the (q*i)th position.

Abstract: A system and method for communicating information signals using spread spectrum communication techniques. PN sequences are constructed that provide orthogonality between the users so that mutual interference will be reduced, allowing higher capacity and better link performance. With orthogonal PN codes, the cross-correlation is zero over a predetermined time interval, resulting in no interference between the orthogonal codes, provided only that the code time frames are time aligned with each other. In an exemplary embodiment, signals are communicated between a cell-site and mobile units using direct sequence spread spectrum communication signals. In the cell-to-mobile link, pilot, sync, paging and voice channels are defined. Information communicated on the cell-to-mobile link channels are, in general, encoded, interleaved, bi-phase shift key (BPSK) modulated with orthogonal covering of each BPSK symbol along with quadrature phase shift key (QPSK) spreading of the covered symbols.

Abstract: A spread spectrum communication system for wirelessly transporting autonomously time-referenced telecommunication data couples the data streams to mutually synchronized multiplexers, outputs of which are encoded and applied to associated I and Q channel spreaders, which spread the respective multiplexed data streams using mutually orthogonal spreading code sequences. The resulting spread I-channel data streams are coupled to I and Q channel summing units outputs of which are applied to respective channels of a QPSK modulator and transmitted to a receiver site. At the receiver the QPSK signals are correlated in despreading correlators and then decoded and demultiplexed to produce data streams, corresponding to those applied to the transmitter.

Abstract: An electronic device (100) for providing a multi-carrier spread spectrum signal. The device (100) has a spread spectrum signal encoder (140) and decoder (160). The encoder has sequence spreading modules (143) and modulators (145) each having a unique carrier frequency relative to all other carrier frequencies of the other modulators (145). The encoder (140) converts a received serial data stream of bits into a plurality of parallel data bit streams of different bit lengths, and expand a received one of the parallel data bit streams into a coded bit sequences. Each of the coded bit sequences have a unique time period relative to all other said coded bit sequence from every other sequence spreading modules (143) of the encoders (140). The decoder (160) decodes received multi-carrier spread spectrum signals into data bit streams.

Abstract: Method and device for estimating a propagation channel The invention relates to a method of estimating a propagation channel, between a source transmitting data and a receiver, using at least one learning sequence which comprises symbols referred to as “pilot symbols” and which is known to the receiver, so as to decode a data signal (digital signal), the signals being sent in successive frames, each frame being partitioned into a specified number of time slots.

Abstract: A method and system is provided for estimating a first wireless communication channel (FWCC) transmitting a data stream from a first antenna system (FAS) to a second antenna system (SAS) in a telecommunication system, the telecommunication system having a second wireless communication channel (SWCC) for transmitting data from the MT to the antenna. First, one or more characteristics of the SWCC (SWCC Characteristics) are analyzed based on the data stream received by the antenna system from the MT. From the data stream received, an initial condition of the FWCC is also extracted.

Abstract: Transmitted signals from plurality of mobile terminals are received at one or more base stations in a Code Division Multiple Access system. The base stations send the received signals to a central processor in the form of complex signal sample streams. The central processor determines the correlations between the spreading codes used by the mobile terminals and combines the interference correlations with channel estimates to form an interference matrix. The central processor uses the interference matrix to process the received signals reduce the interference between signals from different mobile terminals.

Abstract: One aspect of the present invention is a method for combining a direct sequence spread spectrum signal comprising signal components that each may be characterized with a space variable and a time variable comprising the steps of: despreading said signal components; and determining a set of combining coefficients from said signal components using a Minimum Mean Square Error combining method that considers said space and time variables of the signal components in parallel. The Minimum Mean Square Error combining methods may utilize iterative methods such as the Least Mean Squares method or the Recursive Least Squares method.

Abstract: A parallel interference cancellation receiver that reduces impulse response interference using a model of the received signal similar to that used in block linear equalizers. Block linear equalizers comprise decorrelating receivers, zero-forcing receivers, minimum mean square error receivers and the like. The invention comprises an interference computation processor feedback loop for correcting the output of a direct interference canceller. The m iterative process removes interferers from the output symbols of a matched-filter. The PIC receiver uses received signal models of the various block linear equalizers that do not assume that each subchannel consists of several distinct paths. The receiver estimates the impulse response characteristic of each subchannel as a whole.

Abstract: The present invention concerns a multi-user detection method for a receiver in a multi-carrier code division multiple access telecommunication system, each communication to or from a user of the system being coded with a signature, the signal received by said receiver being decomposed into a first plurality of frequency components,

Abstract: A method and apparatus are disclosed for detecting a pilot signal in a wireless receiver using coherent combining/noncoherent detection techniques. Coherent combining/noncoherent detection techniques are used to detect the pilot signal whenever the receiver is already frequency locked, or otherwise known to have a small frequency offset. Conventional noncoherent combining/noncoherent detection techniques are utilized to initially acquire the timing of the forward channel. Once the receiver is frequency locked, coherent combining/noncoherent detection techniques may be used to continuously detect the pilot signals. After the receiver is frequency locked, the residue frequency error is small over several consecutive correlator outputs. The correlator outputs can thus be combined coherently (since the frequency error is known to be small), and the phase dependency is then eliminated by noncoherent detection.

Abstract: A self-tuning duplicating transceiver is provided. The transceiver includes a microprocessor, a transmitter and a receiver. The transmitter includes an electrically tunable radio frequency oscillator, and the receiver includes a counter for determining an edge count associated with a received signal. The microprocessor is programmed to receive an unknown signal with the receiver and use the counter to determine the edge count thereof, and electrically tune the transmitter oscillator to a carrier frequency corresponding to the edge count for the unknown signal.

Abstract: A center and remote sides are connected via a line and perform an initialization sequence to set a transmission speed and to detect gain characteristics of a signal received during the initialization sequence at both sides. Both center and remote sides then inform each other of the detected gain characteristics and correct gain characteristics of future transmission signals based on the informed gain characteristics. Therefore, it is possible for a sender side to perform a gain correction that raises gain amounts of transmission signals according to a decay rate, and for a receiver side to maintain the reception level, which is more than a predetermined value, thereby providing a high-speed data rate.

Abstract: A startup protocol is provided for use in a communications system having a communications line with a master transceiver at a first end and a slave transceiver at a second end, each transceiver having a noise reduction system, a timing recovery system and at least one equalizer all converging at startup of the system. The operation of the startup protocol is partitioned into stages. The first stage includes the step f converging the equalizer and the timing recovery system of the slave while converging the noise reduction system of the master. Upon completion of the first stage the protocol enters a second stage which includes the step of converging the equalizer and the timing recovery system of the master, converging the noise reduction system of the slave, freezing the timing recovery system of the slave, and resetting the noise reduction system of the master.

Abstract: Error display in a multiple carrier modulation format. In a multiple carrier modulation format such as OFDM, displaying error spectrum plots and error time plots. The error spectrum plot shows a set of bar graphs arranged by carrier, each bar graph showing error points for that carrier collected over a plurality of symbol times. The error time plot shows errors over all carriers plotted as a symbol time series. Average errors in both plots may be indicated, and connected to show trends.

Abstract: A method for forming a non-iterative time-domain equalizer (TEQ) and apparatus corresponding thereto. A channel response H(z) is followed by a TEQ response A(z) and a residual output B(z) is chosen so that its degree is less than a cyclic prefix. An error signal is formed so that E(z)=H(z)A(z)−B(z). With a unit input, the error signal is set to zero and B(z)=H(z)A(z). Each signal is expressed as a polynomial, having varying degrees, and a having corresponding coefficients. Once expanded, the coefficients of similar degree can be equated on both sides of the equation. The error signal can then be determined in terms of coefficients corresponding to the TEQ and the residual signal. The coefficients of the channel response can be derived from the channel training estimates. The error signal is minimized and the result is solved for in terms of the desired TEQ coefficients.

Abstract: Transmit amplitude independent adaptive equalizers are provided that compensate for transmission losses in an input signal when the transmit signal amplitude is unknown. Several embodiments are provided, including a first embodiment having an equalizer core, a controllable-swing slicer and an amplitude control loop, a second embodiment having an equalizer core, a fixed-swing slicer and a control loop, a third embodiment having an equalizer core, a variable gain amplifier, and a variable gain amplifier control loop, and a fourth embodiment having an equalizer core, a fixed-swing slicer, a variable gain amplifier, and a variable gain amplifier control loop.

Abstract: Method and apparatus for soft bit computation with a reduced state equalizer. The method assures that the number of states in the equalizer is reduced to obtain acceptable complexity, while also ensuring that soft bit computation is performed for substantially all bits. The method involves computing a first set of soft bits from bits transmitted in a received signal, using a reduced-state trellis with finite non-zero delay, calculating hard decisions in response to the received signal, and also ensuring that substantially all soft bits are computed by employing zero-delay soft decision-making or decision-feedback equalization to compute a second set of soft bits. Furthermore, the hard decisions are used to compute the second set.