A method and system of optical communication are provided. An optical modulator device includes a first and a second waveguide segment, and is configured to modulate an incident optical signal. A first feed-forward equalization (FFE) circuit including an inner first tap and an inner second tap, is configured to equalize the first waveguide segment. A second FFE circuit including a first inner tap and a second inner tap, is configured to equalize the second waveguide segment. An FFE recombination of the first inner tap and the second inner tap of the first and second FFE circuits, is in the electrical domain, respectively. An FFE recombination of the first and second modulation signals, operative to equalize a combination of the first second waveguide segments, is in the optical domain.

Methods and apparatus for implementing adaptive equalization channel extension retimer link-up in high-speed serial links. Under aspects of the proposed methodology, the retimer device intervenes with the adaptive equalization training, training both ends of the link individually between the two end points, and once both of the retimer's receivers are trained, it propagates the receiver readiness indication through from one end point to the other. This allows all sections of the link to train at the same time, and for all devices to transition to data mode at the same time, once all channels have been adapted to and trained. This methodology also applies to cascaded retimer device configurations, where multiple retimers are being used to extend the channel even further.

A receiver is configured to capture a plurality of linearly distorted OFDM symbols transmitted over a signal path. The receiver forms the captured OFDM symbols into an overlapped compound data block that includes payload data and at least one pseudo-extension, processes the overlapped compound block with circular convolution in the time domain using an inverse channel response, or frequency domain equalization, to produce an equalized compound block, and discards end portions of the equalized block to produce a narrow equalized block. The end portion corresponds with the pseudo-extension, and the narrow block corresponds with the payload data. The receiver cascades multiple narrow equalized blocks to form a de-ghosted signal stream of OFDM symbols. The OFDM symbols may be OFDM or OFDMA, and may or may not include a cyclic prefix, which will have a different length from the pseudo-extension.

A receiver includes an interface configured to receive a data signal based on an n-level pulse amplitude modulation (PAM-n) in which n is an integer equal to or greater than 4. The interface may include an analog-digital converting circuit configured to adjust a reference voltage, for distinguishing second bit data from the data signal in a second section, based on first bit data converted from the data signal in a first section and the first bit data converted from the data signal in the second section, the second section being after the first section.

In a mobile communication service system, repeaters can be installed to cover shadow areas where it may otherwise be difficult to transmit and/or receive mobile signals. A radio frequency (RF) repeater that may select between an interference cancellation device and a software-defined radio (SDR) device is provided. The RF repeater can select use of the interference cancellation device in environments or situations that are relatively less complex, and can switch to use of the SDR device instead for environments or situations where more complex frequency processing may be needed and where such frequency processing may be prioritized over interference cancellation to provide better or more effective signal transmissions.

An equalizer circuit includes: a pair of input terminals: a differential amplification circuit outputs, to a pair of output terminals, first signals obtained by amplifying a difference in levels of input signals supplied to the pair of input terminals; and a differential differentiation amplification circuit that outputs, to the pair of output terminals, second signals obtained by amplifying a time-varying change in the difference in the levels of the input signals supplied to the pair of input terminals.

RFID data signals from RFID tags may be recovered by determining the probabilities of transitions between data states between a series of a pairs of signal samples using a set of predetermined probabilities related to data, timing, baud rate and/or phase variables affecting the received signal and processing those determined probabilities to determine the sequence of such transitions that has the highest probability of occurrence. A second set of predetermined probabilities related to transitions in the opposite direction may be used to sequence in a reverse direction. The determination of the sequence representing the RFID tag data may be iterated in both directions until further iterations do not change the determined probabilities.

A multi-channel receiver that includes a first clock recovery unit configured to recover a first clock signal associated with a first optical channel is disclosed. A first coefficient estimation unit estimates a first set of coefficients using the first clock signal. A second clock recovery unit configured to recover a second clock signal associated with a second optical channel using the first clock signal as a reference clock signal. A second coefficient estimation unit estimates a second set of coefficients using the first set of coefficients.

A system and method for setting analog front end in a serial receiver. The serial receiver includes a decision feedback equalizer. During initialization, taps of the decision feedback equalizer other than the zeroth tap are disabled, and the zeroth tap is used to estimate the amplitude of the signal at the output of the analog front end. The analog front end gain is iteratively adjusted until the estimated value of the zeroth tap is within a set range.

In a mobile communication service system, a repeater is installed to cover a shadow area. Provided is a radio frequency (RF) repeater that may select between an interference cancellation device and a software-defined radio (SDR) device.