Abstract: A control system including a DC/DC converter and a control module. The DC/DC converter includes a first inductor and a second inductor. The DC/DC converter is configured to i) receive a first DC voltage and ii) output a second DC voltage. The control module is configured to, during a first operation mode, charge the first inductor while discharging the second inductor, and, during a second operation mode, one of i) charge the first inductor while charging the second inductor and ii) discharge the first inductor while discharging the second inductor. The control module is further configured to initiate the second operation mode in response to detecting a current transient in the DC/DC converter.

Abstract: A network device including a physical layer (PHY) device and an autonegotiation module. The PHY device is configured to interface with N cable pairs, where N is greater than 1. The PHY device includes a cable test module configured to diagnose a short circuit in one of the N cable pairs. The autonegotiation module is configured to i) selectively perform autonegotiation to establish a link with a link partner at one of a first link speed and a second link speed that is lower than the first link speed, and ii) select between the first link speed and the second link speed in response to the cable test module diagnosing the short circuit.

Abstract: An RF receiver image rejection scheme. The RF is received and mixed in two quadrature channels allowing separation of the undesired image portion within the RF signal from the desired portion. The two channels can be summed to allow the image portions to cancel out and form a signal which is predominantly based on the desired portion. Another sum of the two channels can also be made to provide a signal which is primarily based on the image portion. Since there are some components of the image portion even in the compensated desired signal, that signal indicative of the image portion is used to compensate for that undesired portion.

Abstract: A physical layer (PHY) device including i) an input configured to receive a first transmit signal transmitted from a remote device, and ii) an output configured to transmit a second transmit signal from the PHY device to the remote device. The second transmit signal causes interference in a receive signal at the input of the PHY device. The PHY device further including a selection module configured to select a first control signal to cancel the interference in the receive signal when the receive signal does not include the first transmit signal and a second control signal to cancel the interference in the receive signal when the receive signal includes the first transmit signal. The interference includes (i) an echo due to the second transmit signal or (ii) crosstalk due to a third transmit signal output by a local PHY device proximate to the PHY device.

Abstract: A signal receiver includes a data recovery module that generates an equalized data signal and a recovered data signal based on a data input signal. An error module generates an error information signal based on the equalized data signal and an error threshold signal. An eye measurement control module generates an eye characteristic signal based on the recovered data signal and the error information signal.

Abstract: Apparatus and methods relating to channel equalization include a method including: generating a first output signal in a frequency domain based on a communications signal of a channel; determining a first channel response based on the first output signal and one or more pilot signals of the communications signal; generating a first equalized signal based on the first output signal and the first determined channel response; generating a first decision signal based on the first equalized signal; generating an output signal in a time domain based on the first decision signal; determining a second channel response based on the time domain output signal; generating a second output signal in the frequency domain based on the second channel response; generating a second equalized signal based on the first and second output signals and the time domain output signal; and generating a second decision signal based on the second equalized signal.

Abstract: A digital signal processor includes an up-sampling module that samples an input signal and generates up-sampling points. A natural sampling module includes a reference signal generation module that generates a reference signal. A crossing point detection module receives the up-sampling points and the reference signal and uses interpolation to detect intersection points of the input signal and the reference signal. The crossing point detection module determines values of the input signal at first and second evaluation times. The crossing point detection module estimates a current intersection point of the input signal and the reference signal as an intersection of the reference signal and a line that extends between first and second points on the input signal that correspond with the first and second evaluation times. A frequency of the reference signal is variable and a current switching period of the reference signal is not equal to a previous switching period.

Abstract: A system includes a first filter that receives an input signal and comprises N taps to filter postcursor inter-symbol interference (ISI) of the input signal. S taps of the N taps have a coefficient that is limited between ?1 and 0. S and N are integer values greater than or equal to 1. N is greater than or equal to S. A decision feedback equalizer includes a decision circuit that communicates with the first filter. A second filter communicates with an input and an output of the decision circuit.

Abstract: Systems and techniques relating to image cancellation in received communications signals are described. A described technique includes receiving a communications signal including a desired signal and an image signal; generating a leakage tracing signal at a frequency band of the image signal, the leakage tracing signal including a noise signal, a frequency of the leakage tracing signal being within the frequency band of the image signal; and removing the image signal from a signal that is based on the communications signal and the leakage tracing signal to resolve the desired signal, where the removing is based on an addition of the leakage tracing signal to the communications signal. Removing the image signal can include using one or more weights to control one or more filters to resolve the desired signal. The one or more weights can be determined based on the noise signal.

Abstract: A noise-shaping module including a first addition module configured to receive a digital input signal and a filtered output signal. A truncation module is configured to remove selected bits from the digital input signal and output a truncated output signal. The truncated output signal corresponds to the digital input signal with the selected bits removed. A second addition module is configured to output a difference signal. The difference signal is based on a difference between the digital input signal and the truncated output signal. A filter module is configured to generate the filtered output signal based on the difference signal and provide the filtered output signal to the first addition module.

Abstract: A regulated power supply includes an inverter comprising an upper switch and a lower switch that are connected in series. A control module selectively controls the upper switch and the lower switch in one of a pulse width modulation (PWM) mode and a discrete control mode (DCM), receives a feedback signal from an output of the regulated power supply, and switches between the PWM mode and the DCM based on the feedback signal.

Abstract: Methods and systems for filtering include accessing first and second signals produced from an input signal and producing first and second filtered outputs, which correspond to the first and second signals, based on a filtering characteristic. The filtering characteristic can include a first filtering coefficient weighting the first and second signals. The filtering characteristic can include a second filtering coefficient weighting third and fourth signals, the third and fourth signals being produced prior to the first and second signals. The first and second filtering coefficients can include matrices which have non-symmetrical terms.

Abstract: Systems, apparatus and methods are provided for detecting the mode of a received OFDM signal. A received signal may be correlated with one or more time-delayed version of itself resulting in a set of correlation signals. Each correlation signal may be analyzed for one or more characteristics that can be used to determine the symbol length of the received signal. In order to minimize the number of correlations performed, one or more correlations can be used with varying symbol lengths and a fixed guard interval length. The correlation signals can be processed by filters, and the characteristics of the filtered correlation signals can be analyzed to determine the guard interval length of the received signal. In addition to detecting symbol length, the present invention can be used to detect receiver impairment and perform any appropriate compensations.

Abstract: A decision-feedback equalizer (DFE) can be operated at higher frequencies when parallelization and pre-computation techniques are employed. Disclosed herein is a DFE design that operates at frequencies above 10 GHz, making it feasible to employ decision feedback equalization in optical transceiver modules. An adaptation technique is also disclosed to maximize communications reliability. The adaptation module can be treated as a straightforward extension of the pre-computation unit. At least some method embodiments include, in each time interval: sampling a signal that is partially compensated by a feedback signal; comparing the sampled signal to a set of thresholds to determine multiple speculative decisions; selecting and outputting one of the speculative decisions based on preceding decisions; and updating a counter if the sampled signal falls within a window proximate to a given threshold. Once a predetermined interval has elapsed, the value accumulated by the counter is used to adjust the given threshold.

Abstract: In a method for determining timing information in a receiver, a first signal is analyzed to determine a first phase difference with respect to different portions of the first signal, and a second signal is analyzed to determine a second phase difference with respect to different portions of the second signal. The second signal is a frequency domain representation of at least a portion of the first signal. An indication of a carrier frequency offset and a sampling period offset are generated based on the first phase difference and the second phase difference.

Abstract: A system includes a first buffer configured to receive data at a first rate, and output the data at a second rate. A processing module configured to receive the data from the first buffer at the second rate, convert the data into processed data, and output the processed data at a third rate. A second buffer is configured to receive the processed data from the processing module at the third rate, and output the processed data at a fourth rate. The third rate is faster than the fourth rate to avoid a buffer underflow condition in the second buffer. In response to the second buffer reaching a predetermined capacity, the processing module is further configured to enter into a break state in which the processing module temporarily stops both receiving data from the first buffer and outputting the processed data and adjusts the second rate to avoid a buffer overrun condition in the first buffer.

Abstract: A parallel implementation of the Viterbi decoder becomes more efficient when it employs end-state information passing as disclosed herein. The improved efficiency enables the usage of less area and/or provides the capacity to handle higher data rates within a given heat budget. In at least some embodiments, a decoder chip employs multiple decoders that operate in parallel on a stream of overlapping data blocks, using add-compare-select operations, to obtain a sequence of state metrics representing a most likely path to each state. Each decoder passes information indicative of a selected end-state for a decoder operating on a preceding data block. Each decoder in turn receives, from a decoder operating on a subsequent data block, the information indicative of the selected end-state. The end-state information eliminates any need for post-data processing, thereby abbreviating the decoding process.

Abstract: A duty cycle estimator comprises an error generator that compares an output of a switching regulator to a reference to generate an output error, wherein the switching regulator operates in accordance with a switching period. An accumulator determines an accumulated error of the output error over a time period of at least N times the switching period of the switching regulator, where N is an integer. An adjustment determiner adjusts a duty cycle for the switching regulator based on the accumulated error of the output error over the time period.

Abstract: A network interface includes a physical layer (PHY) device that provides an interface to a cable. The PHY device includes an autonegotiation module that selectively performs autonegotiation to establish a link with a link partner based on link parameters and a cable test module that performs a cable test before the autonegotiation begins, that determines a cable performance parameter during the cable test, and that compares the cable performance parameter to a predetermined threshold. The autonegotiation module selects at least one of the link parameters based on the comparison.

Abstract: In a method for setting a local oscillator (LO) frequency in a receiver, a power level of an interfering signal corresponding to a harmonic of an LO signal is determined. The LO frequency is set based on the determined power level of the interfering signal.