A gear shifting technique has been developed in which modulation and equalization are shifted to achieve optional performance. In one form, two or more equalizers, each associated with a demodulator and message decoder, determine if the modulation being used can be increased in complexity in order to increase the channel throughput or determine if the modulation method should be reduced in complexity in order to improve the receiver error performance. The quality metrics can based on which equalizer-demodulator-decoder is set to first detect a valid message. Other factors can be considered with this technique such as a packet-error ratio and a signal-to-noise ratio. In a financial trading system, message erasures can be favored over errored messages by limiting the number of bit or symbol corrections permitted per message to less than the maximum possible for the selected decoding schemes.

A data storage device is disclosed comprising a head actuated over a disk, and a two-dimensional (2D) equalizer comprising a plurality of coefficients. A plurality of stored coefficients are accessed based on a first off-track offset of the head in order to first initialize the coefficients of the 2D equalizer, and then the coefficients of the 2D equalizer are first adapted based at least on a first read signal to generate first adapted coefficients. The plurality of stored coefficients are accessed based on a second off-track offset of the head in order to second initialize the coefficients of the 2D equalizer, and then the coefficients of the 2D equalizer are second adapted based at least on the first read signal to generate second adapted coefficients.

The disclosure provides a terminal device, and frame sending and receiving methods, which relate to the field of communications. The terminal device includes: a confirming component configured to send a broadcast control frame to another terminal device which supports a Wireless Fidelity (Wi-Fi) direct-connecting technology, and confirm that the another terminal device which replies a broadcast response frame supports dynamic frame interaction after receiving the broadcast response frame replied by the another terminal device; and a scanning component configured to send a scanning request frame to the another terminal device which supports the dynamic frame interaction, wherein the field indicating the address of the receiving end in the scanning request frame is null. The length of the frames are greatly reduced by dynamically and self-adaptively adjusting the lengths of interaction frames for the frames in a scanning phase, a discovery phase and an operating phase respectively, thereby effectively solving the problem of power consumption; and meanwhile, a simple physical-connecting solution can be realized, and therefore devices which support Wi-Fi direct-connecting can simply interact with one another.

Advanced detectors for vector signaling codes are disclosed which utilize multi-input comparators, generalized on-level slicing, reference generation based on maximum swing, and reference generation based on recent values. Vector signaling codes communicate information as groups of symbols which, when transmitted over multiple communications channels, may be received as mixed sets of symbols from different transmission groups due to propagation time variations between channels. Systems and methods are disclosed which compensate receivers and transmitters for these effects and/or utilize codes having increased immunity to such variations, and circuits are described that efficiently implement their component functions.

An equalization enhancing module includes: a multiplication unit, multiplying a plurality of equalized signals by a scaling coefficient to obtain a plurality of scaled signals; a determination unit, coupled to the multiplication unit, determining whether the plurality of scaled signals are located in a predetermined region to generate a plurality of determination results; a ratio calculating unit, coupled to the determination unit, calculating an inner ratio associated with a ratio of the plurality of scaled signals located in the predetermined region; and a coefficient calculating unit, coupled to the ratio calculating unit, calculating the scaling coefficient according to the inner ratio.

Embodiments are related to systems and methods for data processing, and more particularly to systems and methods for clock recovery in a data receiver.

An apparatus and a method for generating statistical signals having a characteristic similar to an input signal of a receiving apparatus to determine an optimized filter coefficient through an adaptive equalization algorithm are provided. The apparatus includes a channel estimator, a statistical signal generator, and an adaptive algorithm processor. The channel estimator estimates a channel of a reception signal. The statistical signal generator generates a plurality of signals having the same characteristic as that of a reception signal using a channel determined through a channel estimation process. The adaptive algorithm processor performs an adaptive equalization algorithm using the plurality of generated signals to determine an optimized filter coefficient.

Systems, devices and techniques for receiving a signal comprising a quadrature duobinary modulated signal include performing channel equalization of the received signal using a constant multi-modulus to obtain a set of channel estimation coefficients and a stream of symbols, partitioning, based on modulus, the stream of symbols into three partitions, estimating carrier frequency based on the partitioned stream of symbols, recovering a phase of the signal using a maximum likelihood algorithm, and decoding the partitioned stream of symbols to recover data.

A radio frequency (RF) equalizer includes a coupler including an input port, an output port, a coupling port, and an isolation port; a combination circuit including; a coupling node electrically coupled to the coupling port; a first digitally controlled capacitor (DTC) connected between the coupling node and ground; a resistor connected between the coupling node and ground for controlling a quality factor (Q) of resonance of the equalizer; an isolation node coupled to the isolation port; and a second DTC connected between the isolation node and ground. A system and a method of operation are provided.

A communication device includes a channel estimation unit configured to estimate an impulse response based on signals of sound waves received by each of a plurality of hydrophones, a long delay removal unit configured to remove a long-delay impulse response from the impulse response to generate a post-removal impulse response, a weighting factor calculation unit configured to calculate a weighting factor based on the post-removal impulse response, and a synthesizing unit configured to synthesize the signals received by each of the plurality of hydrophones based on the weighting factor.