Patent application number | Description | Published |
20090170438 | Method and system for reducing signal interference - Signals propagating on an aggressor communication channel can cause interference in a victim communication channel. A sensor coupled to the aggressor channel can obtain a sample of the aggressor signal. The sensor can be integrated with or embedded in a system, such as a flex circuit or a circuit board, that comprises the aggressor channel. The sensor can comprise a dedicated conductor or circuit trace that is near an aggressor conductor, a victim conductor, or an EM field associated with the interference. An interference compensation circuit can receive the sample from the sensor. The interference compensation circuit can have at least two operational modes of operation. In the first mode, the circuit can actively generate or output a compensation signal that cancels, corrects, or suppresses the interference. The second mode can be a standby, idle, power-saving, passive, or sleep mode. | 07-02-2009 |
20100027709 | Method And System For Slicing A Communication Signal - A slicer can receive a communication signal having a level or amplitude that is between two discrete levels of a multilevel digital communication scheme. The slicer can compare the communication signal to a plurality of references such that multiple comparisons proceed essentially in parallel. A summation node can add the results of the comparisons to provide an output signal set to one of the discrete levels. The slicer can process the communication signal and provide the output signal on a symbol-by-symbol basis. A decision feedback equalizer (“DFE”) can comprise the slicer. A feedback circuit of the DFE can delay and scale the output signal and apply the delayed and scaled signal to the communication signal to reduce intersymbol interference (“ISI”). | 02-04-2010 |
20100039923 | Method and System for Crosstalk Cancellation - Signals propagating in one communication channel can generate crosstalk interference in another communication channel. A crosstalk cancellation device can process the signals causing the crosstalk interference and generate a crosstalk cancellation signal that can compensate for the crosstalk when applied to the channel receiving crosstalk interference. The crosstalk cancellation device can include a model of the crosstalk effect that generates a signal emulating the actual crosstalk both in form an in timing. The crosstalk cancellation device can include a controller that monitors crosstalk-compensated communication signals and adjusts the model to enhance crosstalk cancellation performance. The crosstalk cancellation device can have a mode of self configuration or calibration in which defined test signals can be transmitted on the crosstalk-generating channel and the crosstalk-receiving channel. | 02-18-2010 |
20100040180 | Adaptive noise filtering and equalization for optimal high speed multilevel signal decoding - A Signal Conditioning Filter (SCF) and a Signal Integrity Unit (SIU) address the coupled problem of equalization and noise filtering in order to improve signal fidelity for decoding. Specifically, a received signal can be filtered in a manner to optimize the signal fidelity even in the presence of both significant (large magnitudes of) ISI and noise. The present invention can provide an adaptive method that continuously monitors a signal fidelity measure. Monitoring the fidelity of a multilevel signal can be performed by external means such as by the SIU. A received signal y(t) can be “conditioned” by application of a filter with an electronically adjustable impulse response g(t). A resulting output z(t) can then be interrogated to characterize the quality of the conditioned signal. This fidelity measure q(t) can be used to adjust the filter response to maximize the fidelity measure of the conditioned signal. | 02-18-2010 |
20110069604 | Method and System for Signal Emulation - A circuit can process a sample of a signal to emulate, simulate, or model an effect on the signal. Thus, an emulation circuit can produce a representation of a real-world signal transformation by processing the signal according to one or more signal processing parameters that are characteristic of the real-world signal transformation. The emulation circuit can apply analog signal processing and/or mixed signal processing to the signal. The signal processing can comprise feeding the signal through two signal paths, each having a different delay, and creating a weighted sum of the outputs of the two signal paths. The signal processing can also (or alternatively) comprise routing the signal through a network of delay elements, wherein a bank of switching or routing elements determines the route and thus the resulting delay. | 03-24-2011 |
20110169965 | SYSTEMS, METHODS, AND APPARATUSES FOR DETECTING DIGITAL TELEVISION (DTV) COMMUNICATIONS SIGNALS - Embodiments of the invention may provide systems and methods for detecting the presence a DTV signal such as an ATSC DTV signal. The system and methods may be applied to a received RF signal that has been down-converted to a baseband or low-IF digitized signal. The systems and methods may detect a presence of a DTV signal by searching for its characteristic pilot signal, known to reside in a fixed frequency range for all valid DTV signals. This pilot signal may be extracted by processing the baseband or low-IF signal in multiple stages. The first stage may reduce the signal information to that pertaining to the frequency band covering all valid pilot frequencies and commensurately reduces the sampling rate, and hence computational complexity of subsequent operations. A second stage may then efficiently operate on this reduced rate signal to focus on a series of particular pilot frequencies for interrogation. For each such candidate frequency, the cyclostationarity of the signal may be measured and tested for statistical significance relative to the background energy to yield an effective test that is invariant with respect to the background noise level. In a simplified case, this can correspond to measuring the energy in a very tight candidate subband normalized against the energy from a larger subband. Furthermore, the energy in the candidate subband can be taken as the energy in a Fourier series coefficient. | 07-14-2011 |
20110171920 | SYSTEMS, METHODS, AND APPARATUSES FOR REDUCING INTERFERENCE AT THE FRONT-END OF A COMMUNICATIONS RECEIVING DEVICE - Embodiments of the invention may provide for reducing interference in the front-end of a communications receiver. The cancellation circuitry may be utilized in conjunction with a preliminary rejection filter for improved rejection of out-of-band interference from other radio services or circuitry. The cancellation circuit may be placed in parallel with the preliminary rejection filter and may enhance suppression at the interference frequency by matching the gain and phase of the preliminary rejection filter prior to subtracting the matched signal from the preliminary rejection filter output. The cancellation circuit need not necessary know beforehand the characteristics of the preliminary rejection filter, the interference source, or the coupling mechanism, as it may adapt to unknown or varying interferers by adapting the matching gain and phase values based on the output of the preliminary rejection filter at tap points occurring both before and after application of the cancellation signal. | 07-14-2011 |
20110171922 | SYSTEMS, METHODS, AND APPARATUSES FOR REDUCING INTERFERENCE AT THE FRONT-END OF A COMMUNICATIONS RECEIVING DEVICE - Embodiments of the invention may provide for reducing interference in the front-end of a communications receiver. The cancellation circuitry may be utilized in conjunction with a preliminary rejection filter for improved rejection of out-of-band interference from other radio services or circuitry. The cancellation circuit may be placed in parallel with the preliminary rejection filter and may enhance suppression at the interference frequency by matching the gain and phase of the preliminary rejection filter prior to subtracting the matched signal from the preliminary rejection filter output. The cancellation circuit need not necessary know beforehand the characteristics of the preliminary rejection filter, the interference source, or the coupling mechanism, as it may adapt to unknown or varying interferers by adapting the matching gain and phase values based on the output of the preliminary rejection filter at tap points occurring both before and after application of the cancellation signal. | 07-14-2011 |
20110222635 | High-Speed Communication Channel Techniques with Improved Robustness to Timing Uncertainty - A method and system using the principle of generalized maximum likelihood estimation to resolve sample timing uncertainties that are associated with the decoding of communication signals. By using generalized maximum likelihood estimation, sample timing uncertainty can be resolved by taking multiple samples of the received signal within a symbol period and determining which sample best corresponds to the optimal sample timing. The sample which best corresponds to the optimal sample timing can be determined from a timing index which can be calculated from ambiguity indicators that are based on the samples of the received signal. | 09-15-2011 |
20110281524 | System For Reducing Signal Interference - A system for suppressing interference imposed on a victim communication signal by an aggressor communication signal including a circuit that comprises an input port, an output port, and a signal processing circuit connected between the input port and the output port, the signal processing circuit being operative to produce an interference compensation signal at the output port, for application to the victim communication signal, via processing a sample of the aggressor communication signal transmitted through the input port, and the input port being configured to connect to a sampling system that includes a first circuit trace running along a surface of a flex circuit of a portable wireless device that is dedicated to sensing the aggressor communication signal flowing on a second circuit trace running along the surface of the flex circuit. | 11-17-2011 |
20120149306 | Reducing Signal Interference - A method for interference suppression, including receiving a sample of an aggressor communication signal from a sensor embedded in a flex circuit, emulating interference that the aggressor communication signal imposes on a victim communication signal, and suppressing the imposed interference in response to applying the emulated interference to the victim communication signal. In other aspects, the flex circuit comprises a plurality of traces running substantially parallel to one another along a surface of the flex circuit, and the sensor comprises one of the plurality of traces and one of a plurality of traces of another flex circuit. In still other aspects, the flex circuit comprises a plurality of traces running substantially parallel to one another and the sensor comprises a trace of the flex circuit running perpendicular to the plurality of traces running substantially parallel to one another. | 06-14-2012 |
20130064335 | ADAPTIVE NOISE FILTERING AND EQUALIZATION - Processing a signal comprising signal distortions with filters. The filters comprise a first filter configured to a first time scale to compensate for signal distortions within respective symbols of the signal and a second filter configured to a second time scale to compensate for signal distortions among symbols of the signal. A probability estimate is produced based on an output of at least one of the first and second filters. At least one of the first and second time scales is adjusted according to the probability estimate. | 03-14-2013 |
20140103979 | METHOD AND SYSTEM FOR COMPENSATING MODE CONVERSION OVER A COMMUNICATIONS CHANNEL - A circuit can compensate for intra pair skew or mode conversion in a channel by applying a second or corrective mode conversion effect that counters the channel's mode conversion. The circuit can process the common mode signal with a frequency dependent filter prior to injection back into the differential mode. The circuit can implement the reverse mode conversion with passive circuits using integrated resistors and metal oxide semiconductor (MOS) switches. In certain embodiments, such actions can proceed effectively without necessarily consuming active power. | 04-17-2014 |