Abstract: Methods and apparatuses for detecting digital signals in high speed signaling systems. In at least one embodiment, at least one received input signal is combined with a plurality of predetermined reference signals according to a plurality of prior digital signal output states to generate a signal for detecting a present digital signal output state. In one aspect of the invention, a method for determining a digital signal state in a differential signaling system includes: comparing a first differential input signal to a second differential input signal; determining a prior digital signal output state; comparing the first differential input signal to one of a first reference voltage and a second reference voltage; comparing the second differential input signal to one of the first reference voltage and the second reference voltage; and determining a present digital signal output state from the prior digital signal output state and from all of the comparisons.

Abstract: In an optical communication-use receiving circuit of the present invention, the pulse width of the received pulse which is a binary signal corresponding to the signal optical pulse is specified by using an integration circuit and a trigger generating circuit. If the pulse width of the received pulse is not shorter than a predetermined value, a signal having a fixed pulse width is outputted as an output signal from a one-shot pulse generating circuit, so that a pulse having a constant pulse width corresponding to the specified communication speed is outputted. Accordingly, if the pulse width deriving from the signal optical pulse is larger than a certain value, the communication is deemed as a low-speed communication, and a pulse having a constant pulse width corresponding to the communication speed is outputted. As a result, it is possible to realize a small-size receiving circuit and a small-size electronic device which require no external switching-over terminal.

Abstract: A receiver circuit uses two or more comparators to detect the received data signal. Each comparator is set to compare the data signal to a different reference signal. The output signals of the comparators are received into a detector circuit, which provides a third output signal that establishes the logic state of the received signal based on whether or not the output signals of the comparators are equal. Depending on the logic state of the data signal, one of the comparators provides its output signal sooner than the other. Each comparator may be implemented by a differential amplifier. In one embodiment, the reference signals are threshold voltages which may be provided by the tripping voltages at the trip points for the logic HIGH and LOW states.

Abstract: A radio frequency (RF) integrated circuit (IC) includes a local oscillation module, analog radio receiver, analog radio transmitter, digital receiver module, digital transmitter module, and digital optimization module. The local oscillation module is operably coupled to produce at least one local oscillation. The analog radio receiver is operably coupled to directly convert inbound RF signals into inbound low intermediate frequency signals based on the local oscillation. The digital receiver module is operably coupled to process the inbound low IF signals in accordance with one of a plurality of radio transceiving standards to produce inbound data. The digital transmitter is operably coupled to produce an outbound low intermediate frequency signal by processing outbound data in accordance with the one of the plurality of radio transceiving standards. The analog radio transmitter is operably coupled to directly convert the outbound low IF signals into outbound RF signals based on the local oscillation.

Abstract: A receiver includes a memory for storing DC offset amounts generated by an analog circuit; an amplifier; a DC offset amount generator for generating a first offset value and a second offset value to be removed from the received signal amplified at the amplifier; a first DC offset component-removing unit for removing the first DC offset value from the received signal before the amplifier; a second DC offset component-removing unit for removing the second DC offset value from the received signal after the amplifier; and an updating unit for updating the DC offset amount stored in the memory in view of the second DC offset value generated by the DC offset amount generator. A maximum value of the second DC offset value is set larger than a multiplication value of a gain of the amplifier by a minimum resolution value of the first DC offset value.

Abstract: An interface system couples a fixed impedance device to a receiver for transmitting data signals at different data rates at different times. The interface system includes elements that are connected to provide different time constants of responsiveness to data signals of higher and lower data rates without distorting the data signals beyond usability.

Abstract: A data receiver that is capable of precisely detecting data at high speed even at a high frequency after receiving differential reference signals and data in synchronization with a clock signal, and a method for receiving data, are provided. The receiver includes an amplifier which compares differential reference signals with input data and outputs first differential reference signals based on the results of the comparison; and a folded differential voltage sensor which amplifies the difference between the first differential signals in synchronization with a clock signal and detects the input data.

Abstract: Methods and apparatus are disclosed for transitioning a receiver from a first state to a second state using an in-band signal over a differential serial data link.

Abstract: A comparator circuit having reduced pulse width distortion includes a differential amplifier operative to receive at least first and second signals and to amplify a difference between the first and second signals. The differential amplifier generates a difference signal at an output thereof which is a function of the difference between the first and second signals. An output stage is included in the comparator circuit for receiving the difference signal and for generating an output signal of the comparator circuit, the output signal being representative of the difference signal, the output stage having a switching point associated therewith. The comparator circuit further includes a voltage source coupled to the output of the differential amplifier. The voltage source is operative to generate a reference signal for establishing a common-mode voltage of the difference signal generated by the differential amplifier.

Abstract: Spread spectrum receiver architectures and methods are described for reducing interference, particularly the interference observed at a user-end terminal in a W-CDMA 3G mobile communications system. Interpath interference which arises due to non-zero cross and auto correlation of more than one spreading code is suppressed by estimating a transmitted signal stream, or a plurality of such signal streams in the case of a plurality of multipath components, respreading this estimated signal and subtracting non-orthogonal interference contributions from a received signal. The techniques provide an improved bit error rate or equivalently, enhanced capacity for a digital mobile communications network.

Abstract: A system, device, and method for compensation of distortion caused by transmission line effects are disclosed herein. An output port including a feed-forward circuit parallel to the output impedance of an output driver compensates for distortion introduced by transmitting data over a transmission medium. The compensated output driver is utilized to transmit data between devices or circuits connected using conductive traces on printed circuit boards.

Abstract: Provided is a burst mode optical receiver considering a characteristic of an extinction ratio of a received optical signal is provided. By using a peak detector considering a characteristic of an extinction ratio, top and bottom peak voltages of actual burst packets can be precisely detected while not being affected by a DC offset corresponding to an extinction ratio even though burst packets having a DC offset corresponding to the extinction ratio are received. Accordingly, waveform distortion of a signal output from the burst mode optical receiver can be minimized.

Abstract: A transceiver system is disclosed for use in a telecommunication system. The transceiver system includes a transmission circuit with a differential transmitter input coupled via a transmitter input stage to a differential input of a transmission amplifier in an embodiment. The transmitter input stage includes a trimmable resistor, one end of which is coupled to a positive transmit input signal, and the other end of which is coupled to a negative transmit input signal. The transceiver system also includes a receiver circuit with a differential receiver output coupled to a differential input of a receiver amplifier, and further includes a transmission line interface circuit coupled to a differential output of said transmission amplifier and to a differential input of said receiver amplifier. In accordance with other embodiments, the receiver amplifier includes an input stage that includes a first plurality of capacitors and a feedback circuit that includes a second plurality of capacitors.

Abstract: The discrimination phase margin monitor circuit (10) of the present invention comprises a first discrimination circuit (11 and 12) discriminating an input data signal using a clock signal extracted from the input data signal, a second discrimination circuit (13 and 14) discriminating the input data signal using a clock signal with a frequency different from that of the clock and an operation circuit (15 and 16) calculating the exclusive OR of the output signal of the first discrimination circuit and that of the second discrimination circuit and obtaining a phase margin monitor output signal by averaging the exclusive ORs.

Abstract: A high-speed serial linking device with de-emphasis function for receiving a parallel data and accordingly outputting a de-emphasized transmission differential pair. The high-speed serial linking device includes a parallel-to-serial unit, a pre-driver, and an output driver. The parallel-to-serial unit is used to receive a parallel data and further serializes the parallel data into a serial data and a delayed serial data. The pre-driver outputs a data differential pair according to the serial data and outputs a delayed-and-inverted differential pair according to the delayed serial data. The output driver unit is used to receive the data differential pair and the delayed-and-inverted differential pair to accordingly output a de-emphasized transmission differential pair.

Abstract: A PAM-4 data slicer includes first, second, and third comparators which provide first, second, and third thresholds, respectively. Each of the comparators has an offset. The first and third comparators have an offset generating arrangement at their outputs to provide the first and third comparator circuits with symmetrical offsets.

Abstract: A receiver having an array antenna estimates arrival directions of multiple paths that arrive with an angular spread. Consequently, arrival direction estimation accuracy can be ensured without increasing throughput even if the power every path is low by estimating an average arrival direction of an entire set of multiple paths having the angular spread from a result of one angular spectrum by multiple correlation operation units that perform mutual correlation operations with pilot signals for baseband signals received by the array antenna, a path detection unit that detects multiple arrival path receiving timings by generating a delay profile based on output of each of the correlation operation units, a path correlation value synthesis unit that synthesizes a correlation operation value calculated in the multiple correlation operation units and an arrival direction estimation unit that collectively estimates multiple path arrival directions using output of the path correlation value synthesis unit.

Abstract: A loss-of-signal (LOS) condition is detected by sampling input data for a predetermined time period, comparing a magnitude of the sampled input data to a threshold signal strength level, and asserting a LOS indication if the number of samples that have signal strength less than the threshold signal strength level is less than a predetermined value.

Abstract: A communication receiver amplifies a pulse-amplitude-modulated (PAM) signal representing an integer-valued sequence of first data elements (D1) with an adjustable first gain (G1) and digitizes the amplified signal to produce a sequence of second data elements (D2) representing successive magnitudes of the PAM signal. A first automatic gain control (AGC) circuit determines the rate at which magnitudes of the second data sequence elements fall within a first range and adjusts G1 to maintain that rate within a second range. Digital signal processing circuits within the receiver process the second data to produce a sequence of third data elements (D3), each having a real number value substantially equal to a product of a second gain G2 and a corresponding one of the first data elements D1. A slicer rounds the real number represented by each third data sequence element to produce a corresponding integer-valued element of a fourth data sequence (D4).

Abstract: An Improved Signal Receiver Having Wide Band Amplification Capability is disclosed. Also disclosed is a receiver that is able to receive and reliably amplify infrared and/or other wireless signals having frequency bandwidths in excess of 40 MHz. The receiver of the present invention reduces the signal-to-noise ratio of the received signal to ?th of the prior systems. The preferred receiver eliminates both the shunting resistor and the feedback resistor on the input end by amplifing the signal in current form. Furthermore, the receiver includes transconductance amplification means for amplifying the current signal without the need for Cascode stages. Finally, the receiver includes staged amplification to amplify the current signal in stages prior to converting the signal into a voltage output.

Abstract: Methods and apparatus are disclosed for transitioning a receiver from a first state to a second state using an in-band signal over a differential serial data link.

Abstract: The invention relates to a transmitter of radio signals (SMS), which are amplitude-modulated according to a discrete plurality of amplitude levels, in which at least one output power transistor (6) receives, on one of its terminals, a bias-voltage level which is adapted to the amplitude level represented by the instantaneous value of a selection signal (SS) generated by analysis means (11) on the basis of the digital control signals (1). The electrical consumption is hence optimized.

Abstract: A pseudo-differential signaling system uses a plurality of signal lines and a single, common reference voltage. Signal line voltages are interpreted only in comparison to the reference line voltage. Within a receiving circuit, the reference line is buffered prior to its distribution to multiple comparators. The system utilizes an active buffer having a bandwidth that is significantly greater than the resonant input frequency of the receiving circuit. In an alternative embodiment, the signal lines are also buffered. In this embodiment, the buffers are implemented with transistor-based source-followers. The buffer associated with the reference line has a larger current capacity than the buffers associated with the signal lines. In yet another embodiment, a comparator produces a correction signal that is equal to the noise present on the signal lines. This noise is then subtracted from the signal voltages.

Abstract: An orthogonal frequency division multiplexed signal transmitting apparatus executes a time-division multiplexing process that inserts a reference signal at a predetermined interval based on reference signal position information into an information signal to be transmitted. The transmitting apparatus generates an orthogonal frequency division multiplexed signal by digital-modulating the time-division multiplexed signal to radiate into a spatial transmission line. An orthogonal frequency division multiplexed signal receiving apparatus receives the signal from the transmitting apparatus to get the reference signal by demodulating the signal.

Abstract: Disclosed is a method and apparatus for reducing inbound interference in a broadband powerline communication system. Data modulated on first and second carrier frequencies is received via respective first and second lines of the powerline system. A characteristic of at least one of the carrier signals (e.g., phase or amplitude) is adjusted at the receiver in order to reduce the effects of inbound interference on the transmission system. The adjustment parameters may be determined by adjusting the parameters, during a period of no data transmission, until the output of a differential receiver is zero.

Abstract: The present invention includes a transceiver and a method of operating the same that includes in the transmitter a power control circuit that operates on an analog differential signal containing data packets individually. The power control circuit initially transmits a series of data symbols with known values, periodically strobes the transceiver system for correct power levels and incrementally increases the power level of the transceiver until the optimal gain is reached, without exceeding the maximum output power.

Abstract: An adaptive slicer threshold generation system includes a first moving average filter to determine a first average value of a first binary signal. A second moving average filter is included to determine a second average value of a second binary signal. A combiner combines the first average value of the first binary signal and the second average value of the second binary signal to generate a combined output.

Abstract: A wireless communications mobile station (10) includes at least one antenna (240) and a RF transceiver (210,220) containing a direct conversion receiver (1) coupled to the antenna. The direct conversion receiver contains a low noise amplifier (3) for amplifying a received RF signal and for outputting the amplified RF signal to a current switching down-conversion mixer (4). The down-conversion mixer has a first input node for receiving the amplified RF signal, a second input node for receiving a local oscillator (LO) signal for mixing with the amplified RF signal and an output node coupled to an input of an operational amplifier forming a low pass filter (5A). In accordance with an aspect of this invention the low pass filter has a low pass pole generated by a resistor R and a capacitor C coupled in parallel in a feedback path of the operational amplifier, where a low pass comer frequency of the low pass filter is inversely proportional to the product of R and C.

Abstract: A signal compensation circuit compensates for direct-current offset of an input signal by amplifying the input signal with an amplifier having a variable direct-current offset. A low-speed negative feedback loop charges and discharges a capacitor in an integrating circuit according to the direct-current component of the amplified signal. A high-speed negative feedback loop charges and discharges the same capacitor at a faster rate when the amplified signal goes outside an allowable amplitude range. The capacitor potential is used to control the direct-current offset of the amplifier. The allowable amplitude range is adjusted according to the amplitude of the amplified signal. High-speed compensation can thus be combined with a tolerance for runs of identical code levels in the input signal.

Abstract: A communication system including an amplifier, a receiver, an analog to digital converter (ADC) and an insertion phase variation compensation module. The amplifier receives a communication signal. If the amplifier is enabled, the amplifier amplifies the communication signal and outputs the amplified communication signal to the receiver. If the amplifier is disabled, the amplifier passes the communication signal to the receiver without amplifying it. The receiver outputs an analog complex signal to the ADC. The ADC outputs a digital complex signal to the insertion phase variation compensation module which counteracts the effects of a phase offset intermittently introduced into the communication signal when the amplifier is enabled or disabled.

Abstract: A radio frequency (RF) integrated circuit (IC) includes a local oscillation module, analog radio receiver, analog radio transmitter, digital receiver module, digital transmitter module, and digital optimization module. The local oscillation module is operably coupled to produce at least one local oscillation. The analog radio receiver is operably coupled to directly convert inbound RF signals into inbound low intermediate frequency signals based on the local oscillation. The digital receiver module is operably coupled to process the inbound low IF signals in accordance with one of a plurality of radio transceiving standards to produce inbound data. The digital transmitter is operably coupled to produce an outbound low intermediate frequency signal by processing outbound data in accordance with the one of the plurality of radio transceiving standards. The analog radio transmitter is operably coupled to directly convert the outbound low IF signals into outbound RF signals based on the local oscillation.

Abstract: A balanced peak detector circuit adjusts differential voltage signals. In one embodiment, the peak detector uses competing current paths to provide a charging current to a storage capacitor. The charge on the storage capacitor is used to adjust either a transconductance or a transimpedance circuit. An offset current can be used to adjust the charge stored on the capacitor to change a peak-to-peak output voltage from the transimpedance circuit. In one embodiment, the offset current can be adjusted using an adjustable current source. A discharge circuit has been describe that allows a discharge of the capacitor to be controlled.

Abstract: An apparatus for providing multi-symbol signaling includes a multi-symbol encoder circuit. The multi-symbol encoder circuit is operable to encode data into a plurality of symbols, each symbol uniquely defined by a signal transition and a signal region in a carrier signal. A driver circuit, coupled to the multi-symbol encoder circuit, is operable to drive the carrier signal.

Abstract: An Improved Signal Receiver Having Wide Band Amplification Capability is disclosed. Also disclosed is a receiver that is able to receive and reliably amplify infrared and/or other wireless signals having frequency bandwidths in excess of 40 MHz. The receiver of the present invention reduces the signal-to-noise ratio of the received signal to ?th of the prior systems. The preferred receiver eliminates both the shunting resistor and the feedback resistor on the input end by amplifying the signal in current form. Furthermore, the receiver includes transconductance amplification means for amplifying the current signal without the need for Cascode stages. Finally, the receiver includes staged amplification to amplify the current signal in stages prior to converting the signal into a voltage output.

Abstract: An apparatus and method for detecting a signal in an optical data network is disclosed. A peak power level and an average power level are measured for an optical input to an optical detector. A threshold power level is associated with each average power level that is sufficient to distinguish a data signal form optical noise at the average power level. A signal is detected if the measured peak power level exceeds the threshold power level appropriate for the average power level. In one embodiment, a threshold value of a ratio of the peak power level to the average power level is calculated and a signal is detected if the ratio of the measured peak power level to the average power exceeds the threshold value.

Abstract: Two reference voltages and two differential receivers are used to detect low-to-high and high-to-low transitions on an input signal and set a received signal output. One reference voltage is set near but under the electrical high voltage level and the other is set near but above the electrical low voltage level. The reference voltage that is closest to the input signal is designated as the active reference voltage. When the input signal crosses the active reference voltage digital value of the received signal output is changed. When the input signal then crosses the inactive reference voltage, the inactive reference voltage is made the active reference voltage. A dead-time is then waited where input signal crossings of the active reference voltage are ignored. After the dead-time, input signal crossings of the active reference voltage will change the received signal output.

Abstract: An offset control circuit can obtain an output waveform free of fluctuation of duty ratio by canceling offset transitionally varying according to elapsed time even upon reception of an optical signal in burst form significantly variable of level difference, an optical receiver employing the same and an optical communication system. The offset control circuit has offset canceling means for canceling an offset component included in a pair of positive-phase and negative-phase signal and varying transitionally according to elapse of time by using at least one of a peak value and a bottom value of the positive-phase and negative-phase signal.

Abstract: Disclosed is a transimpedance amplifier comprising a multistage amplifier and a feedback circuit coupled between a single ended input terminal and one of a plurality of differential output terminals of the multistage amplifier. The feedback circuit may control an input voltage at the single input terminal to substantially maintain a set or predetermined transconductance between the single ended input terminal and the differential output terminals.

Abstract: Described are a circuit and system to provide an output signal in response to composite input signal comprising an AC signal component and a DC signal component. An amplifier provides an amplified voltage signal in response to a voltage representative of the composite signal. A filter may provide a filtered voltage signal having a magnitude that is representative of a magnitude of the DC signal component in response to the amplified voltage signal. A DC signal removal circuit may substantially remove at least a portion of the DC signal component from an input terminal in response filtered voltage signal.

Abstract: A radio frequency receiver includes an amplifier and a detector that produces a bias control signal based on a signal environment. A bias level of the amplifier is set according to the bias control signal. Bias levels of other receiver circuits may have similarly adjusted bias levels, including buffers, IF oscillators, mixers, and converters. The invention can be used to increase range of linearity, intermodulation immunity and reduce power consumption by reducing the bias level under typical conditions and relying on the bias control to increase bias levels under adverse signal conditions. The invention has advantages where power is at a premium, particularly when a device is in standby mode, including mobile, portable and hand held pagers and wireless telephones and Internet connections. If standby mode operation in non-maximum signal environments dominates the usage of the receiver, then the invention can substantially increase battery life.

Abstract: A physical layer transceiver of a home network station connected to a telephone medium has an architecture enabling adaptation of detection circuitry based on received network signals to enable reliable recovery of data signals. The physical layer transceiver includes an input amplifier that amplifies network signals according to one of 128 gain settings set by a receiver gain control signal. A signal conditioning circuit includes an envelope detector configured for outputting an envelope of the amplified received signal, and an energy detector configured for outputting an energy signal of the amplified received signals. The envelope signal and the energy signal are supplied to slicer threshold circuits, configured for outputting noise, peak, data event and energy event signals based on noise threshold, peak threshold, data transition threshold, and energy threshold signals, respectively.

Abstract: A tracking system and method in an optical communications system utilizing an optical communications beam. In one embodiment, the disclosed optical communications system includes a communications receiver circuit and a tracking circuit. The optical communications system generates a communications signal. The tracking system includes a tracking detector having a plurality of regions coupled to a corresponding plurality of tracking channel circuits. Each of the tracking channel circuits includes an optical detector coupled to receive the optical communications beam. The peak-to-peak amplitude modulation in the optical communications beam is measured by substantially reducing or removing a direct current (DC) offset present in the optical communications beam. In one embodiment, after the DC offset is substantially reduced or removed, the signal is then amplified, mixed with the communications signal and then filtered.

Abstract: A receiver which may be an xDSL receiver has improved dynamic range. The receiver has a first amplifier, a network of four impedances and a variable gain second amplifier. The variable gain second amplifier has an input connected to an ouput of the first amplifier, an output connected to the first amplifier, and a variable gain control input. The gain of the variable gain second amplifier is 1 K , and the pass-band gain of the receiver is K. By controlling the gain of the receiver with an AGC (automatic gain control), the receiver can amplify and filter inputs over a wide dynamic range with lower distortion and without saturation. Alternatively, the gain of the variable gain second amplifier is - 1 K . The four impedances can be arranged to realise low-pass or high-pass filters.

Abstract: An AGC window detector that senses the sum of an in-phase (I) and a quadrature (Q) peak-to-peak signal swing and compares the signal to a reference voltage for producing a desired gain. The primary design issues of the detector is to achieve a very low voltage offset and a low power dissipation. The detector is part of the AGC circuits in the I/Q path of a wireless receiver. The signals Imax, Imin, Qmax and Qmin are the positive and negative peak values of the in-phase and the quadrature waveforms, respectively. They are generated by a peak detector. Thus the differential in-phase and the differential quadrature amplitudes are Imax−Imin and Qmax−Qmin,, respectively. A resulting differential in-phase signal is added to a resulting differential quadrature signal by the detector and compared to the reference voltage to determine if the resulting signal is greater than a maximum reference voltage, less than a minimum reference voltage or within the maximum and minimum voltages.

Abstract: A burst mode receiving apparatus having an offset compensating function and a data recovery method thereof, including an intermediate value detector to detect and output an intermediate value of an input signal input from an outside source in response to a switching control signal; an amplifier to amplify and output a difference between the input signal and a reference value; an offset compensator to generate a compensation signal having a level varied corresponding to the amplified result input from the amplifier and a compensation control signal; a summing portion to add the compensation signal and the intermediate value to output the added result as the reference value to the amplifier; and a controller to generate the switching control signal and the compensation control signal corresponding to a result obtained by analyzing the amplified result input from the amplifier and a reset signal input from the outside source.

Abstract: A DC offset correction method and apparatus. In a differential system, a DC offset correction loop includes a gain stage (104) having a differential input, a gain G and a differential output. A DAC circuit (130) provides a correction DC signal at the inputs to produce differential output signals Vo′ and {overscore (Vo)}′. A controller (120) corrects the DC offset by stepping the DAC circuit (130) to change the correction DC signal by an amount equal to approximately (Vo′−{overscore (Vo′)})/Gx, where GX is the gain G times the gain of the DAC expressed in volts per DAC step. A similar algorithm can be applied to single ended systems wherein a single ended VOFFSET is corrected by an amount equal to approximately VOFFSET/Gx.

Abstract: An automatic gain control circuit for an optical receiver couples the low level signal produced by an optical detector to a signal amplifier, preferably a double-ended differential amplifier with the optical detector output fed into the high input and the low input coupled to ground, the gain of which is controlled by a negative feedback circuit. The feedback circuit comprises a signal level detection circuit coupled to the amplifier output, such as high-speed Schottky diodes acting in conjunction with an operational amplifier. The Schottky diodes are coupled to ground through AC coupling capacitors, and oriented in opposite directions, so when the amplified signal exceeds a conduction threshold of the Schottky diodes the capacitors are respectively charged and drained, establishing a voltage difference between the input terminals of the operational amplifier.

Abstract: A network receiver is configured for receiving a base band carrier signal from another network transceiver via a network medium. A variable gain amplifier generates an amplified base band signal. An A/D converter generates a sequence of sample values representing the base band signal in response to the amplified base band signal. A gain control circuit monitors the sequence of sample values for a plurality of monitoring intervals in a sample time period, determines a range for each monitoring interval, and determines a gain setting for the variable gain amplifier.

Abstract: A data pulse receiver includes a data regenerator and a peak detector, both having set-reset flip-flops (RS-FFs) to generate hysteresis which is varied based on its tail current provided to the RS-FF. The regenerator regenerates data from a differential signal derived from an incoming data signal. The peak detector monitors the peak level of the differential signal derived and its output adjust automatically the tail currents of the data regenerator and the peak detector. The receiver also includes impedance matching networks connected to the data regenerator and the peak detector. The input impedances for both networks are essentially the same. The tail currents for the two RS-FFs of the regenerator and the peak detector are essentially equal and it ensures precise cancellation of non-linear effects.

Abstract: An optical communication device includes a receiving circuit that generates an accurate voltage signal from received light. The voltage signal is then used to quickly and accurately determine emission information which is used to adjust the emission level of an associated light emitting diode, by varying the drive current supplied to the light emitting diode. The receiving circuit has a light receiving element that generates a current from received light. The current is converted into first and second current signals using a fixed distribution ratio. First and second amplifiers convert the first and second current signals to first and second voltages. A current control circuit is connected to the light receiving element and the second amplifier and controls the amount of the first current signal using the second voltage.