Abstract: A method and system are provided for allowing mobile device users to participate in an online survey community by entering opinions and reading opinions of other through their mobile devices. The mobile devices need not support the same protocol as the server that manages and provides the survey information. In particular, a system is provided in which users of WAP-enabled mobile phones can enter opinion information into their WAP phones immediately after an event that is the subject of a survey, even though a Web server that uses a protocol not supported by the phones manages the survey data. Further, a feature is provided to defer the transmission of the opinion data from the phone, thereby allowing the opinion data to be batched, or to be entered even when the phone network is not available.

Abstract: A translation apparatus retains a first correlation between a Mobile IPv6 terminal's home address and virtual IPv4 address. When the Mobile IPv6 terminal transmits a packet to said IPv6 network with a care-of address specified as the packet's source address and a home address specified in an extension header, the translation apparatus changes the packet's source address to a virtual IPv4 address that corresponds to the packet's home address in accordance with the first correlation, and then transmits the packet to an IPv4 network. Mobile IPv6 terminal-to-IPv4 terminal communication can then be established between an IPv6 network to which Mobile IPv6 terminals are connected and an IPv4 network to which IPv4 terminals are connected.

Abstract: A method of scheduling upstream bandwidth. This method comprises: 1) anticipating the need for the upstream bandwidth in advance of any specific request for said upstream bandwidth; and 2) scheduling the upstream bandwidth in accordance with such need.

Abstract: An apparatus, system and method for converting data in a first packet format, having overhead data in the form of headers and/or trailer padding, into a second, variable-length packet format, in which some of the header and/or trailer overhead is removed during conversion in order to more efficiently utilize the limited bit rate capacity of a link which will convey the data in the second format. Embodiments include a communication subnetwork for interconnecting a plurality of users to a wide area network through a wireless link, an Asynchronous Transfer Mode (ATM) switch for converting ATM cells into a variable-length packet format, and a convergence system for converting ATM cells into data packets in Media Access Control (MAC) format.

Abstract: A synchronous data link signal is generated for supply between digital television equipment in a studio and an RF transmitter. The synchronous data link signal includes first data to be encoded at a first data rate, second data to be encoded at a second data rate less than the first data rate, and a map defining the relative amounts and placement of the encoded first and second data in the synchronous data link signal. The first data is in the form of first output data packets of a predetermined size. The second data and the map data are multiplexed so as to provide more than one second output data packet having the predetermined size. The first and second output data packets are then multiplexed so as to provide the synchronous data link signal.

Abstract: A system is described comprising: a first node coupled to a second node by a communications network, the first node and second node communicating digital and/or analog signals over the communications network; the first node comprising a power output selector module to apply a specified voltage to the communications network to power one or more devices communicatively coupled to the communications network; and the second node using the voltage to provide power to one or more electrical components.

Abstract: Systems and methods for automatically discovering the configuration of network and/or communication facilities are provided. The determination generally involves receiving and/or sending at least one test message or packet with special characteristics that normally would be filtered by filtering/forwarding entities in connectionless routed cores, but normally would be forwarded by connectionless communication facilities. If the communication facilities do not contain the filtering/forwarding entity, the at least one test packet will be forwarded or passed through the communication facilities. If the at least one test packet is filtered or not passed, then at least two scenarios are possible. First, the at least one test packet may be filtered and may be silently discarded in which case a determination that the network did not pass the at least one test packet may be made based upon a timeout of a counter.

Abstract: The invention features an apparatus and an associated method for illuminating a target area. The apparatus includes reflectors defining a first optical cavity. The first optical cavity defines a first set of longitudinal modes. The apparatus includes a first gain medium defining a first gain band. The first gain medium is configured to cause a plurality of the longitudinal modes of the first set to oscillate over an oscillation band within the first gain band when the first gain medium is pumped at an operative level. The apparatus includes a first optical waveguide positioned within the first optical cavity. The first optical waveguide has a length selected to cause a temporal coherence length of light emitted from the first optical cavity to be shorter than a scattering distance associated with the target area.

Abstract: Lasers, such as in laser structures, can include two or more semiconductor structures that are substantially identical or that include the same semiconductor material and have substantially the same geometry, such as in closely spaced dual-spot two-beam or quad-spot four-beam lasers. The lasers can also include differently structured current flow or contact structures or different wavelength control structures. For example, current flow or contact structures can be differently structured to prevent or otherwise affect phase locking, such as by causing different threshold currents and different operating temperatures.

Abstract: Aspects of the present invention are directed to the use of optical gain structures that include alternating layers of gain medium and transparent heat conductors in which the gain medium itself functions as a correction optic. The gain medium changes to an optimum or desired shape because of the thermal changes occurring as the materials of the optical gain structure(s) reach a desired optical output condition. At the desired optical output conditions, the gain medium conforms to a desired shape. The desired shape may be, for example, that of an optical surface of a transparent heat conductor. By designing the initial shape of the gain medium such that the physical contact with the transparent heat conductor is maximized at the desired optical output conditions, conductive heat transfer between the gain medium and heat conductor(s) is maximized at the desired optical output condition.

Abstract: A cooling system for use in with a transmissive optical element of a high average power laser (HAP). The system includes at least one optically transmissive element (TOC) that is held by a differential pressure in thermal contact with a heat sink assembly. In one embodiment, the heat sink assembly includes an optically transparent heat conductor (THC) attached to at least one face of the TOC. A vacuum formed between adjacent faces of the TOC and THC urges the facing planar surfaces into thermal contact with one another. Waste heat generated in the TOC is conducted to the THC. The temperature gradient inside the TOC is maintained substantially parallel to the direction of a laser beam being directed through the THC so that a given phase front of the beam exposes TOC material to the same temperature. As a result, the TOC does not perturb the phase front of the laser beam.

Abstract: Intersubband semiconductor lasers (ISLs) are of great interest for mid-infrared (2-20 ?m) device applications. These semiconductor devices have a wide range of applications from pollution detection and industrial monitoring to military functions. ISLs have generally encountered several problems which include slow intrawell intersubband relaxation times due to the large momentum transfer and small wave-function overlap of the initial and final electron states in interwell transitions. Overall, the ISL's of the prior art are subject to weak intersubband population inversion. The semiconductor device of the present invention provides optimal intersubband population inversion by providing a double quantum well active region in the semiconductor device. This region allows for small momentum transfer in the intersubband electron-phonon resonance with the substantial wave-function overlap characteristic of the intersubband scattering.

Abstract: A semiconductor light emitting device comprises: a stacked body of semiconductor including an active layer; a ridge stripe protruding and extending in a first direction on a first major surface of the stacked body; dummy ridges protruding on the first major surface of the stacked body on both sides of the ridge stripe; and a slit formed on the first major surface of the stacked body. The ridge stripe includes at least a portion of a waveguide that guides light emission generated by injected current. The slit extends along a second direction which crosses the first direction, and divides one of the dummy ridges.

Abstract: A semiconductor tunable laser (10) and an interferometer (12) coupled to the tunable laser (10) are monolithically fabricated in a semiconductor heterostructure. The laser also comprises a buried ridge stripe waveguide laser. The interferometer (12) has a semiconductor optical amplifier (38) coupled in each arm. A cross-gain semiconductor optical amplifier converter is coupled to the interferometer (12). The semiconductor optical amplifier (38) coupled in each arm is biased so that an optical path length difference between the two arms is in antiphase which results in destructive interference. The output of the tunable laser (10) is coupled to a coupler. A semiconductor optical amplifier (38) is used as a gain controller for the semiconductor optical amplifiers in the interferometer (12) to allow wavelength conversion over a larger range of input signal powers.

Abstract: A modulation channelization and demodulation system based on orthogonal bipolar spreading vectors is provided that permits a variable information rate to be transmitted without inducing envelope fluctuations and permits multiple access without requiring the transmitter amplifiers to support the combined information rate of all users. The modulation system uses the vectors of a Hadamard matrix to form communication channels. The information rate on any channel may be doubled by using half the vector length to transmit information. The vector that is not non-orthogonal-in-the-half to the rate-doubled vector is preferably deactivated. In the same fashion, higher information rates may be provided through truncation of the transmission vector and the elimination of the resultant non-orthogonal vectors. A multi-channel receiver including a Fast Hadamard Transform structure comprised of controllable modified logic cells for performing the multi-rate communication of the present invention is illustrated.

Abstract: System and method for code acquisition in a wireless communications system with a delay lock loop. A preferred embodiment comprises assigning a delay lock loop (DLL) to each path in a received signal with multipath, adjusting each DLL to maximize sample strength, grouping samples that are less than a first threshold apart into groups, adjusting DLL timing of samples in groups, regrouping groups that are less than a second threshold apart, applying a group decision to regrouped groups, and repeating the regrouping and applying until all groups are greater than the second threshold apart.

Abstract: The invention concerns a procedure for estimating unknown amplification factors of a received CDMA signal, which encompasses a plurality of code channels, in which respectively an input signal from a symbol plane is split on a symbol plane through splitting with a split code (?ab(?)) in a chip plane. The procedure is executed in the following steps: formation of a cost function dependent upon estimated values of all unknown amplification factors, partial differentiation of the cost function according to estimated value of the unknown amplification factors, formation of a matrix-vector-equation on the basis that all partial differentials of the cost function are zero and thus a minimum of the cost function is present, and the computation of at least some of the matrix coefficients of the matrix-vector-equation with a correlation function on the symbol plane.

Abstract: An integrated circuit that performs data demodulation on partially despread symbols includes a despreading unit, a channel compensation unit, and a symbol combiner. The despreading unit despreads input samples and provides despread symbols for a first code channel with a first spreading factor. The channel compensation unit multiplies the despread symbols with channel estimates and provides demodulated symbols. The symbol combiner combines groups of demodulated symbols to obtain recovered data symbols for a second code channel with a second spreading factor that is an integer multiple of the first spreading factor. The channel compensation and symbol combining are dependent on whether or not transmit diversity is used. For a TDM design, despread symbols for multiple first code channels are processed in a TDM manner, one channel at a time, to obtain recovered data symbols for multiple second code channels. The channel compensation unit and symbol combiner can be operated in a pipelined manner.

Abstract: The present invention discloses an apparatus for initial synchronization and cell search in a CDMA system based on multipath energy window. The apparatus perform initial synchronization and adjacent cell search by using multipath energy window based on the processing method of multipath energy window. The apparatus can be implemented based on a parallel correlator bank. This invention also provides the application of the apparatus to a coherent spreading receiver.

Abstract: A method for estimating an SNR-related parameter, such as ES/N0, from one or more symbols. The number of symbols within a predetermined number of symbols that fall within one or more collection areas is counted. The count is then associated with a value of the SNR-related parameter. This association may be performed through one or more lookup tables. In one application, a scaling factor is derived from the count. The scaling factor may be used to scale symbols before they are quantized and inputted into a trellis decoder such as a log-MAP decoder.

Abstract: Multi-layered motion or still video compression includes, in an encoder or encoding function aspect of the invention, separating the video signal into low-frequency and high-frequency components, processing the low-frequency components of the video signal to generate synthetic high-frequency components, the low-frequency components or a data reduced version of the low-frequency components comprising a main or base layer, and generating the difference between the synthetic high-frequency components and the actual high-frequency components, the difference comprising an error or enhancement layer signal. A decoder or decoding function aspect of the invention processes the main layer to generate synthetic high-frequency components and combines the synthetic high-frequency components, main layer and enhancement layer to provide a decoded output signal similar to the video signal applied to the encoder.

Abstract: An apparatus comprising an output circuit, a first processing circuit and a second processing circuit. The output circuit may be configured to generate an output data stream in response to (i) a first intermediate signal, (ii) a second intermediate signal, and (iii) a third intermediate signal. The first processing circuit may be configured to generate the first intermediate signal in response to (i) a processed video signal and (ii) a prediction flag. The second processing circuit may be configured to generate (i) the processed video signal, (ii) the second intermediate signal and (iii) the third intermediate signal in response to an input video signal.

Abstract: A prediction error generating unit generates a predictive vector from the motion vectors of a plurality of adjacent blocks, and obtains a difference from a target vector. A plurality of variable-length coding units respectively encode the output of the prediction error generating unit with different encoding methods. A determining unit estimates the accuracy of the predictive vector generated by the prediction error generating unit based on the degrees of non-uniformity of the motion vectors of the plurality of adjacent blocks. A selecting unit selects one of the encoding results obtained by the plurality of variable-length coding units.

Abstract: A moving picture coding apparatus (10) for performing inter-picture predictive coding on pictures constituting a moving picture is provided with a coding unit (103) for performing predictive error coding on image data; a decoding unit (105) for performing predictive error decoding on an output from the coding unit (103); a reference picture memory (117) for holding output data from the decoding unit (105); and a motion vector detection unit (108) for detecting forward and backward motion vectors on the basis of decoded image data stored in the memory (117) When coding a B picture, a picture that is timewise closest to the target picture is used as a candidate picture for forward reference, and an I or P picture that is timewise closest to the target picture is used as a candidate picture for backward reference. The moving picture coding apparatus (10) so constructed can improve coding efficiency of a B picture to be subjected to bidirectional predictive coding.

Abstract: A method and system of encoding and decoding digital video content. The digital video content comprises a stream of pictures which can each be intra, predicted, or bi-predicted pictures. Each of the pictures comprises macroblocks that can be further divided into smaller blocks. The method entails encoding and decoding each of the smaller blocks in each picture in said stream of pictures in either frame mode or in field mode.

Abstract: A method and system of encoding and decoding digital video content. The digital video content comprises a stream of pictures which can each be intra, predicted, or bi-predicted pictures. Each of the pictures comprises macroblocks that can be further divided into smaller blocks. The method entails encoding and decoding each of the smaller blocks in each picture in said stream of pictures in either frame mode or in field mode.

Abstract: A method and system of encoding and decoding digital video content. The digital video content comprises a stream of pictures which can each be intra, predicted, or bi-predicted pictures. Each of the pictures comprises macroblocks that can be further divided into smaller blocks. The method entails encoding and decoding each of the smaller blocks in each picture in said stream of pictures in either frame mode or in field mode.

Abstract: A method and system of encoding and decoding digital video content. The digital video content comprises a stream of pictures which can each be intra, predicted, or bi-predicted pictures. Each of the pictures comprises macroblocks that can be further divided into smaller blocks. The method entails encoding and decoding each of the smaller blocks in each picture in said stream of pictures in either frame mode or in field mode.

Abstract: A method for estimating a transmission channel from a multicarrier signal transmitted through said transmission channel, comprising real pilot symbols and so-called pure imaginary pilot symbols, consists in selecting one or several values zk of the received signal corresponding respectively to one or several real pilot symbols, and one or several values zl of the received signal corresponding respectively to one or several pure imaginary pilot symbols. The pilot symbols are sufficiently close both in frequency and in time such that it can be assumed that the fading of the signal through the transmission channel has a complex value ? substantially identical for the symbols. An estimated value {circumflex over (?)} of ? for the pilot symbols concerned is then determined by minimizing a least square equation involving the values zk and the values zl.

Abstract: Communication systems include a transmitter that modulates a radio signal transmitted from two differently polarized antennas during a state time in which a wave state of the radio signal conveys information and is based on one or more polarization states selected from a constellation of polarization states comprising at least three polarization states. The communication system includes a receiver that intercepts the radio signal by two differently polarized antennas during the state time, and demodulates the signal. The polarization states may identify user devices or may quantify a portion of the information intended for a user device.

Abstract: A method of determining transmission parameters for a wireless transceiver is disclosed. According to the method, a state table is loaded into a transceiver. The state table includes a plurality of states, each of which has a set of transmission parameters associated therewith. Based upon characteristics of the signals received from a signal source, the transceiver is assigned a first state. The received signals are received and processed using the set of transmission parameters associated with the first state. It is determined whether an observed behavior of the received signals exceeds a threshold associated with the first one of the plurality of states. The transceiver is assigned a second state when the behavior exceeds the threshold. The received signals are received and processed using the set of transmission parameters associated with the second state.

Abstract: In some embodiments of the present invention the nature of an input signal is identified and the amplification of a pre-amplifier and a power amplifier in a transmitter system are modified responsive to whether the momentary content of the input signal is a preamble or data and to the modulation rate of the input signal. In some other embodiments sets of amplification factors are set to reduce in-band noise at the antenna of the transmitter system.

Abstract: A power amplifier comprises a level-discretization modulator (210) and a mixing and amplifying stage (225), in combination with a properly designed negative feedback path. The feedback path forms an error compensation loop together with a properly selected forward path. The forward path includes at least the mixing and amplifying stage (225), which provides frequency up-conversion to the radio frequency band and switch-based amplification. The negative feedback path includes a down-conversion mixer (280) for down-conversion to the initial frequency band, and compensates for distortion caused by components of the forward path.

Abstract: A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of regions having a range ?? beginning at each phase angle ?n, said first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function at phase angles lying inside the regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded, the second function being different from Y=sin ?.

Abstract: A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of regions having a range ?? beginning at each phase angle ?n, said first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function at phase angles lying inside the regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded, the second function being different from Y=sin ?.

Abstract: A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of data regions, the first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the data regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function different from Y=sin ? at phase angles lying inside the data regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded. The third harmonic of the waveform may be generated and used.

Abstract: A radio receiver includes a low noise amplifier, intermediate frequency mixing stage, complex bandpass filter, a single analog to digital converter, a 1st digital mixing module, and a 2nd digital mixing module. The low noise amplifier is operably coupled to amplify a modulated radio frequency (RF) signal to produce an amplified modulated RF signal. The intermediate frequency mixing stage is operably coupled to mix the amplified modulated RF signal with a local oscillation to produce a modulated IF signal. The complex bandpass filter filters an I and Q component of the modulated IF signal to produce a filtered IF signal. The single analog to digital converter is operably coupled to convert the filtered IF signal into a digital IF signal. The 1st and 2nd mixing modules each receive the digital IF signal and mix the digital IF signal with an in-phase and quadrature digital local oscillation to produce a 1st baseband signal component and a 2nd baseband signal component.

Abstract: A quadrature transceiving system for compensating a direct current (CD) offset, a gain imbalance and a phase imbalance between an I-channel signal and a Q-channel in a quadrature transmitting system is disclosed. The quadrature transceiving system includes a transmitter for detecting a DC offset, a gain imbalance and a phase imbalance by using an average of a data aided signals included in a RF transmitting signal and compensating one of the I-channel and the Q-channel based on the detected imbalances and DC offset; and a receiver for detecting a DC offset, a gain imbalance and a phase imbalance by varying loop filter gain and compensating one of the I-channel and the Q-channel based on the detected imbalances and DC offset.

Abstract: A direct conversion receiver includes a receiver for receiving a signal including multiple components at different receiving frequencies belonging to a frequency band. A mixer mixes the signal components into a base band signal comprising I- and Q branches. A converter converts the analog base band signal into a digital signal. The receiver includes a measuring unit for measuring power levels of the signal components in pairs, where one component in the pair belongs to an upper sideband of the frequency band and one component in the pair belongs to a lower sideband of the frequency band. An estimator estimates, when either the upper sideband component or the lower sideband component dominates in power over the component in the pair, a frequency-independent phase imbalance, a frequency-dependent phase imbalance and a gain imbalance, and a compensator compensates the estimated imbalances to at least one of the I- and Q-branch signals.

Abstract: Disclosed herein is a method and apparatus used to measure the number of time a multi-valued data signal transmitted from either a communication device of subsystem deviates across and into one or more bounded areas or zones as defined by an eye mask that is overlaid onto an eye diagram. The present invention employs an iterative process to accumulate and display mask violation that might result from a data signal transmitted from a target device or communications subsystem that deviates across the boundaries either above or below or into the center of the eye diagram. In addition, the present invention also has the ability to isolate particular threshold voltage-delay points along the boundaries above or below and around the perimeter of the mask polygon of the eye diagram where mask violations have occurred. This provides the ability to supply additional information and feedback about the behavior and performance of the targeted device or subsystem being tested.

Abstract: A method of decoding, in one particular embodiment, an IEC 60958 biphase coded data stream comprising determining the maximum period in the data stream without a transition; determining a first threshold corresponding to a period of time less than the maximum period and greater than the data bit period; determining whether a considered transition corresponds to a data bit or a preamble based on the time between the considered transition and a preceding transition compared with said first threshold; and if the considered transition corresponds to a data bit, determining the data bit based on the considered transition and the preceding considered transition.

Abstract: Apparatus for iterative detection and demodulation of M-ary orthogonal signals (MOK) and signals using Complementary Code Keying (CCK). The apparatus comprises a non-coherent detector that is used during the first iteration and in subsequent iterations uses a coherent detector that is responsive to a soft decoder that is responsive to the detectors. For MOK signals use is made of the first chip, which is known, obviating the need for a pilot signal.

Abstract: A method and apparatus for displaying substantially noise-free segments of serial data waveforms. The method comprises the steps of dividing an acquired waveform into a plurality of waveform slices and categorizing each of the plurality of waveform slices according to at least a sequence of N bit values prior to a bit value being observed. The waveform slices in each category are then averaged resulting in an average pattern for each category. Each of the averaged patterns is then displayed on a display in an overlayed manner.

Abstract: A method and apparatus for the signal synchronization of an orthogonal frequency division multiplexing system includes a delay conjugate multiplication module, a phase processor and an edge detector. It provides estimates for the boundaries of inter-symbol interference free region by utilizing the characteristics of a guard interval in combination with the techniques of the delay conjugate multiplication module, phase differential operation, symbol-by-symbol average operation, and edge detection. The method determines a fixed optimal threshold for directly separating the inter-symbol interference region in a mobile environment to obtain an inter-symbol interference free version of symbol information.

Abstract: Methods of recovering data in a received signal sent in a communications media are disclosed. Composite channel impulse responses are first estimated. Channel-tap locations are then assigned to suppress the interference noises by sequential search schemes or heuristic search schemes based on estimated composite channel impulse responses. A sequential search scheme optimizes a predetermined design criterion in a sequential manner. Also described are recursive evaluations of the design criterion and the inverses of the noise covariance matrices based on the composite channel impulse response during a sequential search. A heuristic search scheme selects channel-tap locations based on a set of pre-selected channel-tap locations. The set of pre-selected channel-tap locations is determined according to the estimated composite channel impulse response. A method of estimating energy levels of known interference sources is also described.

Abstract: In a method for correlative estimation of a mobile radio channel on the basis of a training sequence (TS) which is transmitted via the mobile radio channel, a sequence of P received symbols is correlated with a subsequence of length P of the training sequence, in order to calculate a first estimated channel coefficient (?0(1)). Furthermore, the same sequence of P received symbols is correlated with at least some of the subsequences of the training sequence (TS) shifted through ±1, ±2, . . . , ±(Lt?1) symbol positions, in order to calculate a number of further estimated channel coefficients (?±1(1),?±2(1), . . . ,?±(Lt?1)(1)).

Abstract: An asynchronous FIFO buffer communicates data between first and second clock domains. The FIFO buffer includes a shift register that accepts and shifts out data at a relatively high output frequency required for the second clock domain. The input data is loaded into the shift register in synchronization with the output clock; input data is not loaded into the shift register on each cycle of the output clock, however, because the input clock is slower than the output clock. A clock comparison circuit compares the input and output clocks and tracks the history of data transfers into the shift register to determine whether a given input datum should be loaded into the shift register during a given period of the output clock. The clock comparison circuit writes input datum into the shift register periodically, skipping write cycles as necessary so that input and output data rates match.

Abstract: In the data recovery circuit of the invention, a first group of sampling clock pulses is used for sampling approximately the central portions of the data bits in an incoming data stream to produce a first sampled data stream, while a second group of sampling clock pulses is used for sampling approximately the transition portions between every two adjacent data bits in the incoming data stream to produce a second sampled data stream. By detecting the resemblance of each bit in the second sampled data stream to the corresponding two adjacent bits in the first sampled data stream, a phase detection and correction circuit determines an early condition or a late condition for the phases of the sampling clocks and produces a signal to correct the phases of the sampling clocks by shifting the phases backwards or forwards. According to the invention, sampling clocks with lower frequencies can be used for sampling, and the phase error can be corrected to obtain the correct data recovery.

Abstract: A symbol synchronization device that enables effective symbol synchronization establishment and synchronization holding for an arbitrary spread code sequence.

Abstract: A programmable logic device (“PLD”) includes high-speed serial interface (“HSSI”) circuitry. The HSSI circuitry includes clock signal circuitry that allows various components of the HSSI circuitry to be clocked in different ways to facilitate use of the HSSI circuitry to support a number of different communication protocols. Some of the HSSI clock signals may be routed through the clock distribution network of the associated PLD logic circuitry. The HSSI circuitry may include phase compensation buffer circuitry to compensate for possible phase differences across the interface between the HSSI circuitry and the associated PLD logic circuitry.