Abstract: A data equalization system includes a data clock input configured to receive a clock signal. There is an input node operative to receive a data signal of transmission symbols that change state synchronously with the clock signal. There is a first tap coupled to the input node. A second tap is configured to receive a variation of the data signal. At least one of a weight of the first tap or a weight of the second tap is modulated by a dynamic control parameter that repeats synchronously with each transmission symbol.

Abstract: A filter includes a series arm resonant circuit connected between input/output terminals, and a parallel arm resonant circuit connected between a node on a path connecting the input/output terminals and ground. The series arm resonant circuit includes a series arm resonator having a band width ratio wider than the band width ratio of the parallel arm resonant circuit and a capacitor connected to the series arm resonator.

Abstract: An EMI-hardened multimedia interface device compatible with high-speed DisplayPort data transmission incorporates coupled isolation transformers on the source and sink sides for transmitting high-pass DisplayPort main data lane signals across a shielded cable assembly. The multimedia interface includes a bidirectional auxiliary data channel with source-side and sink-side isolation transformers. An extended-range EMI hardened interface device may prevent signal loss over longer cable runs by using the transformer in a BALUN configuration and utilizing coaxial cabling and source-side RF amplifiers to boost high-frequency gain. Interface devices may incorporate source-side and sink-side BALUNs or tri-filar RF transformers with AC coupling via serial capacitors to improve efficiency at high frequencies.

Abstract: Analog echo cancellation with Digital-to-Analog Converter (DAC) noise suppression may be provided. First, a test signal may be sent through an echo cancellation pathway during a downstream silence period and an upstream silence period. The echo cancellation pathway may comprise an electronic element. Next, a loopback response signal may be received in response to sending the test signal through the echo cancellation pathway. Then a channel response model may be created that characterizes a channel response of the loopback response signal and a non-linear model may be created that characterizes a non-linearity of the electronic element. Next, for a downstream signal, a non-linear component may be generated based on the created non-linear model. The generated non-linear component may be convolved with the created channel response model. The convolved non-linear component may then be subtracted from an upstream signal.

Abstract: In a communications system that conducts differential data via a pair of wires, AC common mode noise is undesirably coupled to the wires in a noisy environment. A hybrid common mode choke (HCMC) attenuates the AC common mode noise while passing the differential data to a PHY. The HCMC includes a CMC (windings with the same polarity) and a differential mode choke (windings with opposite polarities). The CMC attenuates the AC common mode noise, and the DMC passes the attenuated AC common mode noise to termination circuitry to eliminate it. Also disclosed is a technique for Kelvin sensing the DC voltage at the pair of wires, in a PoDL system, by detecting the voltage on wires that do not carry DC current, so as to provide a more accurate measurement.

Abstract: The present communication system has a communication terminal (100) and a communication terminal (200) that are respectively provided with a memory for writing and reading using error correction coding/decoding. The communication terminal (100) transmits data to the communication terminal (200) in a high speed mode or normal mode. In high speed mode, the communication terminal (100) reads coded data written in a first memory (112) and transmits the coded data to the communication terminal (200) without decoding. The receiving-side communication terminal (200) writes the received data in a second memory (212) without coding, and decodes the data when said data is read.

Abstract: A signal receiving circuit having an equalizer calibration function. The signal receiving circuit includes a sampling circuit, output driver and clock signal generator. The sampling circuit captures samples of a data signal in response to a sampling clock signal. The output driver outputs an equalizing signal to an input of the sampling circuit in response to a first clock signal. The clock signal generator adjusts a phase of the first clock signal to achieve phase alignment between transitions of the equalizing signal and transitions of the data signal.

Abstract: A system and method in accordance with a non-limiting aspect minimizes echo return loss in a communications system. The dial tone is broken on an analog telephone line connected to a hybrid circuit having selectable impedance configurations and that interfaces a digital communications circuit and the analog telephone line. A white noise signal as a test call is inserted through the hybrid circuit onto the analog telephone line corresponding to a selected impedance configuration. The returned white noise signal is used for measuring the echo return loss. The test call is dropped. This process is repeated at different impedance configurations to obtain echo return loss measurements at each of the impedance configurations. The optimum impedance setting configuration is determined based on the results and applied to the hybrid circuit and typically set during a running telephone configuration.

Abstract: Unshielded twisted pair (UTP) termination circuits, UTP termination circuit systems, and methods of terminating an UTP circuit are provided. UTP termination circuits can include a plurality of resistors in parallel, where each of the plurality of resistors is configured to be coupled to one of a plurality of unshielded twisted pairs of an UTP cable, a shunt resistor is coupled in series with the plurality of parallel resistors, and a capacitor is connected to ground in series with the shunt resistor.

Abstract: An apparatus which accepts a connection of an external telephone and connects to a telephone line includes a first controller configured to control line impedance via the telephone line, a detecting unit configured to detect a ringing signal received from the telephone line, a determining unit configured to determine whether the external telephone captures a telephone line, and a second controller configured to invalidate the control over line impedance by the first controller in a case where the apparatus is a standby state and validate the suppression of the control over ringer impedance by the first controller in a case where the detecting unit detects the ringing signal and the determining unit determines that the external telephone does not capture a telephone line.

Abstract: An antenna tuner is placed between a Power Amplifier (PA) and an antenna. The antenna tuner includes programmable components that can be tuned in order to effect an impedance translation between the antenna and the PA output. In an embodiment, the antenna tuner is adapted dynamically based on changes in the impedance of the antenna. In another embodiment, the antenna tuner is controlled based on measurement of the voltage reflection coefficient S11.

Abstract: Disclosed are a method and a circuit for impedance matching. The method comprises: a peripheral impedance detection module detecting an impedance of a subscriber telephone and outputting information about the impedance of the subscriber telephone; an analog switch switching module providing an impedance matching path between the impedance of the subscriber telephone and an impedance matching module according to the information about the impedance of the subscriber telephone output by the peripheral impedance detection module; the impedance matching module providing a corresponding impedance through the impedance matching path provided by the analog switch switching module to match to said impedance of the subscriber telephone. By the present invention, the impedance matching is achieved when a wireless access box communicates with telephones with various impedance modes.

Abstract: Various embodiments described herein are directed to methods and systems for blind mode adaptive equalizer system to recover complex valued data symbols from the signal transmitted over time-varying dispersive wireless channels. For example, various embodiments may utilize an architecture comprised of a channel gain normalizer, a blind mode equalizer with hierarchical structure (BMAEHS) comprised of a level 1 adaptive system and a level 2 adaptive system, and an initial data recovery subsystem. The BMAEHS may additionally be comprised of an orthogonalizer for providing a faster convergence speed. In various architectures of the invention, the BMAEHS may be replaced by a cascade of multiple equalizer stages for providing computational and other advantages. Various embodiments may employ either linear or decision feedback configurations. In the communication receiver architectures, differential encoders and decoders are presented to resolve possible ambiguities.

Abstract: A receiver may be operable to receive a signal. A sequence estimation module of the receiver may generate estimated symbols corresponding to the received signal. The generating of the estimated symbols may use tap information associated with one or both of a pulse shaper via which the signal was transmitted and an input filter of the receiver. The sequence estimation module may generate a reconstructed signal based on the estimated symbols and the tap information. A feed forward equalizer (FFE) of the receiver may adapt a plurality of tap coefficients of the FFE based on the reconstructed signal. The signal may be equalized via the FFE. The adaptation of the tap coefficients of the FFE may be based on a least-mean-square (LMS) process for minimizing a mean square of the error signal. An output signal of the FFE may comprise a power gain compensation.

Abstract: A filter for filtering a received signal to attenuate an interferer therein, the interferer having a component at an interferer frequency, and the filter comprising: an intermediate filter providing a passband and a stopband; a first frequency converter configured to form a first intermediate signal by frequency-shifting an input signal derived from the received signal such that a component of the input signal at the interferer frequency is shifted to a frequency in the passband of the intermediate filter, and to input the first intermediate signal to the intermediate filter so as to cause the first intermediate signal to be filtered by the intermediate filter to form a second intermediate signal; a second frequency converter configured to form a cancellation signal by frequency-shifting the second intermediate signal such that a component of the second intermediate signal in the passband of the intermediate filter is shifted to the interferer frequency; and a cancellation unit configured to cancel the cancel

Abstract: A method and circuit for matching impedance, wherein, a peripheral impedance detection module detects the user telephone impedance and outputs information about the user telephone impedance; an analog switch handover module provides an impedance matching path between the user telephone impedance and an impedance matching module according to information about the user telephone impedance output by the peripheral impedance detection module; the impedance matching module provides a corresponding impedance to match the user telephone impedance through the impedance matching path provided by the analog switch handover module. The above-mentioned technical scheme realizes the impedance matching when communicating between a wireless access box and telephones with different impedance modes. The matching process is automatic and flexible and does not need the manual configuration, and the realization technology is simple and reliable, and the cost is low.

Abstract: Decision feedback equalization (DFE) circuitry and method for equalizing data signals over a wide range of data rates. By using delayed and controlled versions of the recovered data clock to retime the equalized data signal for feedback via the DFE taps, correct feedback signal timing is maintained and jitter tolerance is increased at high data rates.

Abstract: Transmit equalization over high speed digital communication paths may be compensated in a receiver for a probe on that path. In one example, a probe input provides a signal from an electronic communications path, the signal having been processed by a transmit equalizer. A filter circuit processes the signal to compensate for the transmit equalizer, and a decoder decodes the processed signal and produces an output for use by test equipment.

Abstract: An internet protocol telephone includes a substrate having an input and an output that are capable of being connected to the internet protocol (IP) network. A relay is disposed on the substrate and is connected between the input and the output of the substrate. The relay includes first and second native FETs that have a threshold voltage of approximately zero volts. Therefore, the relay is nominally turned-on, even when little or no voltage (or power) is applied to the IP telephone substrate, as during the discovery mode of IP telephone operation. During discovery mode, The IP phone is configured to be responsive to extended link pulses and block data packets that are associated with legacy devices. Data packets have a higher signal duration and are more continuous than extended link pulses. The IP phone includes a switchable ground that is connected to the gates of the native devices, and is controlled by a rectifier and filter circuit that are connected to the substrate input.

Abstract: A system and method in accordance with a non-limiting aspect minimizes echo return loss in a communications system. The dial tone is broken on an analog telephone line connected to a hybrid circuit having selectable impedance configurations and that interfaces a digital communications circuit and the analog telephone line. After the telephone line is quiet, a white noise signal as a test call is inserted through the hybrid circuit onto the analog telephone line corresponding to a selected impedance setting configuration. The returned white noise signal is used for measuring the echo return loss corresponding to the selected impedance setting configuration. The test call is dropped. This process is repeated with multiple test calls each at a selectively different impedance setting configuration to obtain echo return loss measurements at each of the impedance setting configurations. The optimum impedance setting configuration is determined based on the results determined from the different test calls.

Abstract: A voltage-mode line driving circuit is provided. The voltage-mode line driving circuit includes a driving circuit, the driving circuit receiving, as an input signal, a feedback signal, and outputting an output signal. The voltage-mode line driving signal also includes an adaptive tuning circuit coupled to the driving circuit, the adaptive tuning circuit receiving as input signals the feedback signal and the output signal and adaptively outputting a modifying signal to the driving circuit which modifies the feedback signal.

Abstract: An Internet Protocol (IP) telephone has a constant impedance filter that is capable of being continuously attached to the physical layer of a computer chip in the IP telephone. The constant impedance filter is located outside the physical layer and is connected to a relay on the physical layer. The relay is configured using native FET devices, which are normally conductive without a supply voltage. Therefore, the relay is capable of operating during the discovery mode of IP telephone operation, where no power is applied to the substrate. Rectifier circuits rectify an incoming signal during discovery mode, and apply the rectified signal to the gate of the relay to improve conductivity of the relay. This allows for faster detection of the IP telephone during discovery mode. During normal operation mode, voltage is applied to the physical layer, and the relay is opened by grounding the native devices.

Abstract: In one embodiment, the present invention includes an apparatus having a first pair of low voltage operational amplifiers to generate an output representative of an absolute value difference of first and second line voltages of a subscriber loop, and a third low voltage operational amplifier having an input coupled to the output of the first pair of low voltage operational amplifiers to filter the output and to provide a switch control signal for a switching regulator that provides a voltage used to generate the first and second line voltages. The apparatus may include additional circuits such as a limit circuit to limit the input to the third low voltage operational amplifier and one or more speedup circuits to reduce a filter time constant of the third low voltage operational amplifier during a ringing mode of the subscriber loop.

Abstract: The invention relates to methods and a high speed communication device that allow one of a plurality of high speed communication devices connected to a transmission line having a normal impedance to effectively receive data. The high speed communication device can include a transmission line interface connected to the transmission line, a receiver connected to the transmission line interface, and a transmitter selectively coupled to the transmission line interface. The transmitter can have an impedance substantially equal to the normal line impedance. The high speed communication device can present a high impedance to the transmission line with respect to the normal line impedance when the transmitter is not coupled to the transmission line interface, and the high speed communication device can present an impedance to the transmission line that is substantially equal to the normal line impedance when the transmitter is coupled to the transmission line interface.

Abstract: A system, method and apparatus is described that permits a user to configure or select the manner in which an audio signal transmitted or received over a telephony system, such as a wideband telephony system, is shaped or equalized. An implementation of the present invention allows a user to configure or select equalization control parameters on a call-by-call basis. Furthermore, an implementation of the present invention allows a user to associate equalization control parameters with a party initiating a call and/or a party receiving the call, thereby facilitating automated equalizer adjustment at call connection based on an identification of the calling party and/or the called party.

Abstract: A multi-stage differential amplifier and method provides a gain versus frequency warping response characteristic that equalizes a transmission line of a given length to compensate for frequency-dependent attenuation. The warping response characteristic comprises the inverse of the attenuation versus frequency characteristic of the line, and affords a substantially flat system gain response over a predetermined frequency spectrum. The individual amplifier stages employ operational amplifiers, and are designed using SPICE simulations such that the individual responses of the stages are tailored so they combine to provide the required overall warping response to compensate the line.

Abstract: An efficient baseband predistortion linearization method for reducing the spectral regrowth and compensating memory effects in wideband communication systems using effective multiplexing modulation technique such as wideband code division multiple access and orthogonal frequency division multiplexing is disclosed. The present invention is based on the method of piecewise pre-equalized lookup table based predistortion, which is a cascade of a lookup table predistortion and piecewise pre-equalizers, to reduce the computational complexity and numerical instability for desired linearity performance with memory effects compensation for wideband transmitter systems.

Abstract: A method of signal communication includes receiving a selection signal, and selecting a selected frequency range used for a multi-carrier signal communication from a set of predetermined frequency ranges for signal communication depending on the selection signal. The set of predetermined frequency ranges includes a first frequency range and a second frequency range including the first frequency range.

Abstract: A system includes a plurality of modules which are configured for determining a suitable impedance for a modem. The plurality of modules send signals with a plurality of signal frequencies to a telephone and receive feedback signals from the telephone under each of a plurality of impedances of the modem, compute a total decibel value of the feedbacks under each impedance, and determine a suitable impedance according to a minimum total decibel value from the plurality of total decibel values.

Abstract: A digital signal line echo reduction adaptor is configured to connect adjacent to a first end of a bridgetap line. The bridgetap line has a second end connected to a carrier communication line. The digital signal line echo reduction adaptor reduces an effect of echo from the bridgetap line on a rate of data transmission over the carrier communication line.

Abstract: This circuit is a back terminated transmission line driver which dissipates no outgoing power across its back terminating resistor by using both a voltage source and a current source.

Abstract: A high-speed bit stream interface module interfaces a high-speed communication media to a communication Application Specific Integrated Circuit (ASIC) via a Printed Circuit Board (PCB). The high-speed bit stream interface includes a line side interface, a board side interface, and a signal conditioning circuit. The signal conditioning circuit services each of an RX path and a TX path and includes a limiting amplifier and a clock and data recovery circuit. The signal conditioning circuit may also include an equalizer and/or an output pre-emphasis circuit. The limiting amplifier applies respective gains to the RX path and to the TX path that are based upon respective dynamic ranges of the incoming signals.

Abstract: Programmable plain old telephone line impedance matching circuits that provide an accurate, integrated programmable termination and source impedance for a telephone line interface circuit (SLIC). The accurate matching of this programmable termination and source impedance with the termination impedance of the 2 Wire connection eliminates signal reflections on this connection and therefore removes the echo, which echo can lead to reduced signal quality in packetized VOIP systems. The programmable integrated impedance matching circuits of this invention use a programmable time continuous amplifier preferably in combination with a double sampling programmable switched capacitor feedback stage (sampling twice per clock cycle by sampling on the positive and negative phases of a non-overlapping clock cycle).

Abstract: A bipolar pulse forming transmission line module and system for linear induction accelerators having first, second, third, and fourth planar conductors which form a sequentially arranged interleaved stack having opposing first and second ends, with dielectric layers between the conductors. The first and second planar conductors are connected to each other at the first end, and the first and fourth planar conductors are connected to each other at the second end via a shorting plate. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short at the first end a high voltage from the third planar conductor to the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

Abstract: The present invention relates to a method for attenuating near-end crosstalk between a remote received signal and a locally transmitted signal in a bidirectional signal transmission wherein said method comprises the step of producing an analog automatic feedback-driven correction loop in order to provide a no-correlation between said transmitted and received signals and to a hybrid circuit for enabling said method.

Abstract: A system and method for measuring a characteristic impedance of a transmission-line comprises transmitting energy to the line, and shortly after measuring the voltage/current involved and thus measuring the equivalent impedance. The measured characteristic impedance may then be used in order to determine the termination value required to minimize reflections. In another embodiment, the proper termination is set or measured by adjusting the termination value to achieve maximum power dissipation in the terminating device. The equivalent characteristic impedance measurement may be used to count the number of metallic conductors connected to a single connection point. This abstract is not intended to limit or construe the scope of the claims.

Abstract: A channel memory length selection method for wireless communication systems is provided. The method comprises estimating an initial channel impulse response (CIR) for the wireless communication system; determining a first refined CIR with a first group of taps and a second refined CIR with a second group of taps based upon the initial CIR, number of the second group of taps being less than number of the first group of taps; and selecting either the number of the first group of taps or the number of the second group of taps as the channel memory length according to an energy concentration criterion in regard to the first refined CIR and the second refined CIR.

Abstract: An xDSL modem having an adaptive hybrid termination impedance. The modem has a transformer with two cores, one connected to the modem's receiver and the other connected to the modem's transmitter. The two cores share an adjustable termination impedance. The modem determines which impedance setting to use, based on one or more measurements of channel loss, local echo power and received power from the far end transmitter, and the like.

Abstract: A supply circuit for supplying a two-wire line comprises a first resistor connected between a first supply voltage potential and a first two-wire line connection of a two-wire line, a current-limiting device connected between a second two-wire line connection of the two-wire line and a second supply voltage potential and providing the two-wire line with a limited current on the basis of a variable setting potential, and an impedance-matching device connected between the second two-wire line connection and the second supply voltage potential and providing the variable setting potential on the basis of a reference potential and a voltage across the current-limiting device. The first resistor has a first impedance and the impedance-matching device and the current-limiting device form a second impedance being present at the second two-wire connection. The first and second impedances are essentially the same.

Abstract: A field-mounted process device with multiple isolated connections includes a connection that can be an input or an output. The given input or output can couple to multiple sensors or actuators, respectively. The process device can be wholly powered through its communication I/O port. The process device includes a controller adapted to measure one or more characteristics of sensors coupled to an input connection and to control actuators coupled to an output connection. The controller can be further adapted to execute a user generated control algorithm relating process input information with process output commands.

Abstract: A direct access arrangement (DAA) device configured to interface a security alarm modem with a phone network. The DAA device comprises a receive optical isolator (OI) module and first and second transmit OI modules. The transmit OI modules are joined in parallel with one another to receive signals from the security alarm modem and convey the signals to the phone network. The receive IO and first and second transmit OI modules may each be interconnected to at least partially cancel distortion generated by the first and second transmit IO modules.

Abstract: A communications cabling front-end architecture that achieves solid echo cancellation and lower noise performance by combining an echo-cancellation circuit and an equalizer function at the same point, at the most front-end of the system.

Abstract: A method for detecting inductive elements in a communication line, including the processes of: inputting a detecting signal to an end of the communication line; sampling the time domain voltage vector of one end of the communication line; generating the amplitude-frequency characteristic curve of the differential input impedance of one end of the communication line according to the time domain voltage vector; determining the number of the inductive elements in the communication line according to the number of the apexes or zeros on the curve. The present invention also discloses a device for detecting inductive elements in a communication line. By the present invention, the automatic detections of the number of inductive elements such as load coils or phone splitters in the communication line are implemented with the exact detection and the high efficiency, thereby lowering the cost of detecting failures of communication line.

Abstract: A method of selecting an optimum impedance for a loop start trunk line, comprising successively applying respective ones of a plurality of impedance settings to the loop start trunk line, for each impedance setting measuring the impulse response of the trans-hybrid echo path by applying audio test signals to obtain a time-domain trans-hybrid transfer function and deriving a frequency-domain spectrum representative of trans-hybrid loss, and then calculating figure of merit of the transfer function based on the power spectrum. Once all impedance settings have been tested, the optimum impedance is selected as the impedance setting associated with the highest calculated figure of merit.

Abstract: A system and method for transferring data between a transmitter and a receiver over a single conductor is disclosed. During a data transfer operation of bit of information, the voltage level on the conductor is changed from a first voltage level to a second voltage level and maintained at the second voltage level for a predetermined duration of time. The predetermined duration of time is determined by the logical state of the data bit being transmitted. Upon expiration of the predetermined duration of time the voltage level on the conductor is driven back to substantially the first voltage level.

Abstract: An authentication process for authenticating a battery to a cellular telephone includes the step of receiving a challenge from the cellular telephone at the battery over a single wire conductor. In response to the challenge, the seed values are retrieved from the memory and a response is generated based upon the challenge and the seed values. The response is transmitted back to the cellular telephone from the battery over the single conductor so that a comparison with a similar response generated by the cellular telephone may be made.

Abstract: An internet protocol telephone includes a substrate having an input and an output that are capable of being connected to the internet protocol (IP) network. A relay is disposed on the substrate and is connected between the input and the output of the substrate. The relay includes first and second native FETs that have a threshold voltage of approximately zero volts. Therefore, the relay is nominally turned-on, even when little or no voltage (or power) is applied to the IP telephone substrate, as during the discovery mode of IP telephone operation. During discovery mode, The IP phone is configured to be responsive to extended link pulses and block data packets that are associated with legacy devices. Data packets have a higher signal duration and are more continuous than extended link pulses. The IP phone includes a switchable ground that is connected to the gates of the native devices, and is controlled by a rectifier and filter circuit that are connected to the substrate input.

Abstract: Disclosed are a system, method and device for generating an equalized signal from an input signal. Symbols in the equalized signal may be detected on each of a sequence of symbol intervals to recover a symbol value in the symbol interval. A feedback coefficient may be applied to a symbol value recovered in a previous symbol interval to generate the equalized signal in a current symbol interval. The feedback coefficient may be generated based, at least in part, on an estimated error associated with the equalized signal. The estimated error associated with the equalized output signal from among a plurality of candidate estimated error values.

Abstract: A digital communication system for transmitting and receiving Digital Visual Interface (DVI) communication data signals and Display Data Channel (DDC) communication signals over a transmission line comprises an open-loop equalizer circuit and a DDC extension circuit. The open-loop equalizer circuit is operable to receive DVI communication signals transmitted over the transmission line and output equalized DVI communication data signals. The DDC extension circuit is operable to inject a boost current at the receive end of the transmission line during a positive transition in the DDC communication signal, and clamp the receive end of the transmission line during a negative transition of the DDC communication signal.

Abstract: An impedance blocking filter circuit is provided for use in telecommunication systems for interconnecting between incoming telephone lines and customer's terminal equipment so as to unconditionally block impedances above 20 KHz due to the customer's terminal equipment from an ADSL network unit and/or home networking interface unit. The filter circuit includes first, second, and third inductors connected in series between a first input terminal and a first common point. A first resistor has its one end connected also to the first common point and its other end connected to a first output terminal. Fourth, fifth and sixth inductors are connected in series between a second input terminal and a second common point. A second resistor has its one end also connected to the second common point and its other end connected to a second output terminal. A capacitor has its ends connected across the first and second common points.