Abstract: A Fourier transform unit (111) performs Fourier transform on a digital signal on a time axis to generate a frequency domain signal which is a signal on a frequency axis. A filter unit (113) equalizes the frequency domain signal in a frequency domain using N first coefficients. An inverse Fourier transform unit (112) performs inverse Fourier transform on the frequency domain signal processed by the filter unit (113) and returns the frequency domain signal to the digital signal on the time axis. That is, the Fourier transform unit (111), the inverse Fourier transform unit (112), and the filter unit (113) compensate for waveform distortion included in the digital signal using an equalization process (that is, frequency-domain equalization (FDE)) in the frequency domain. A first coefficient setting unit (114) sets N first coefficients used by the filter unit (113) using m (provided N>m) second coefficients.

Abstract: Isolation circuits for digital communications and methods to provide isolation for digital communications are disclosed. An example isolation circuit includes an isolation barrier, a burst encoder in a first circuit, and an edge pattern detector in a second circuit. The example isolation barrier electrically isolates the first circuit from the second circuit. The example burst encoder generates a first pattern in response to receiving a rising edge on an input signal and generates a second pattern in response to receiving a falling edge on the input signal. The example edge pattern detector detects the first pattern or the second pattern received from the burst encoder via the isolation barrier, sets an output signal at a first signal level in response to detecting the first pattern, and sets the output signal at a second signal level in response to detecting the second pattern.

Abstract: A phase interpolator circuit that includes an interpolator suitable for generating synthesized clocks through synthesizing two multi-phase clocks; and an interpolation code generator suitable for generating an interpolation code for controlling the interpolator in response to a shift request. The interpolation code generator generates the interpolation code so that a (K+1)-th multi-phase clock is output as the synthesized clock when a phase of the synthesized clock is to be changed from a phase between K-th and (K+1)-th multi-phase clocks to a phase between (K+1)-th and (K+2)-th multi-phase clocks in response to a multi-shift-up request.

Abstract: Methods and devices are described for overcoming insertion loss notches in RF systems. In one case programmable impedances are used to move an insertion loss notch outside a frequency band of interest.

Abstract: Systems and method for improving performance of a radio frequency system are provided. One embodiment describes a radio frequency system, which includes an antenna that wirelessly transmits analog electrical signals at a desired transmission frequency; a feedback receiver that determines a feedback signal, which includes a portion of a transmitted analog electrical signal via a coupler; and a controller that determines location and magnitude of spurious emissions transmitted at frequencies other than the desired transmission frequency by comparing the feedback signal with a desired signal, in which the desired signal includes a digital electrical signal that does not contain noise introduced by the radio frequency system; and instructs the radio frequency system to adjust operational parameters used to transmit the analog electrical signals when the magnitude of the spurious emissions exceeds a spurious emissions limit at the determined location.

Abstract: A system, method, and apparatus according to various embodiments are disclosed herein to enable a signal in space scheme to have improved signal penetration within buildings and other attenuated environments. The disclosed enhanced signal delivery method transmits multiple bursts in a successive pattern that is known by a receiver on the ground. This successive transmission pattern of bursts effectively creates a longer correlation sequence that allows a receiver to more readily be able to pull the signal out of the noise and, thus, allows a receiver located in a more stringent, attenuated environment to receive a signal where it previously was unable to do so.

Abstract: Described are systems and apparatuses to mitigate the timing margin loss caused by inter-symbol interference (ISI) in high speed input/output (I/O) interfaces. Data dependent jitter (DDJ) compensation techniques that may be utilized in the transmission or receiving circuitry of the I/O interface, including capturing bit data values of a data signal prior to an identified data transition, and delaying/advancing the transmission/reception the data signal or a corresponding clock signal based on these bit data values.

Abstract: A system for hybrid self-interference cancellation includes a transmit coupler that samples an RF transmit signal, a RF self-interference canceller that transforms the sampled RF transmit signal to an RF self-interference cancellation signal, an IF self-interference canceller that transforms a downconverted version of the RF transmit signal to an ISRF self-interference cancellation signal, and a receive coupler that combines the RF and ISRF self-interference cancellation signals with an RF receive signal.

Abstract: An embodiment of a receiver includes signal- and data-recovery units. The signal-recovery unit is configured to recover a first component of a first signal that is received simultaneously with a second signal having a second component, the first and second components including approximately a frequency. And the data-recovery unit is configured to recover data from the first signal in response to the recovered first component. For example, such a receiver may be able to receive simultaneously, and over the same channel space, multiple orthogonal-frequency-division-multiplexed (OFDM) signals that include one or more of the same subcarrier frequencies, and to recover data from one or more of the OFDM signals despite the frequency overlap. A receiver with this capability may allow an increase in the effective bandwidth of the channel space, and thus may allow more devices (e.g., smart phones) to simultaneously share the same channel space.

Abstract: The teachings herein present a method and apparatus that implement and use a factorized precoder structure that is advantageous in terms of performance and efficiency. In particular, the teachings presented herein disclose an underlying precoder structure that allows for full PA utilization. According to this structure, an overall precoder is constructed from a conversion precoder and a tuning precoder. The conversion precoder comprises a block diagonal matrix and has 2?k/2? columns, where k is a non-negative integer. Each tuning precoder has the following properties: all non-zero elements are constant modulus; every column has exactly two non-zero elements; and every row has exactly two non-zero elements; two columns either have non-zero elements in the same two rows or do not have any non-zero elements in the same rows; and two columns having non-zero elements in the same two rows are orthogonal to each other. If row m in a tuning precoder column has a non-zero element, so does row m+?k/2?.

Abstract: Pre-distorted transmitters operable over a wide range of frequencies including a plurality of predetermined frequency bands are provided. The transmitters include a programmable digital up-converter and a programmable digital down-converter, an ADC, a DAC, a power amplifier and at least one analog filter arranged along a transmit signal path and a feedback signal path.

Abstract: Embodiments include systems and methods for applying a controllable early/late offset to an at-rate clock data recovery (CDR) system. Some embodiments operate in context of a CDR circuit of a serializer/deserializer (SERDES). For example, slope asymmetry around the first precursor of the channel pulse response for the SERDES can tend to skew at-rate CDR determinations of whether to advance or retard clocking. Accordingly, embodiments use asymmetric voting thresholds for generating each of the advance and retard signals in an attempt to de-skew the voting results and effectively tune the CDR to a position either earlier or later than the first precursor zero crossing (i.e., h(?1)=0) position. This can improve link margin and data recovery, particularly for long data channels and/or at higher data rates.

Abstract: System, method and computer program product for setting phase control codes to (in-phase) I and (quadrature) Q rotators to a first code pair, different by enough to produce a phase difference between the rotator outputs sufficient to be detected with minimal error by a phase-to-voltage converter. Auxiliary trim DACs are then adjusted according to calibration logic until a comparator output detects a phase difference between the I and Q rotators are within tolerable limits. The resulting trim codes are stored for both the codes in the pair. These trim codes along with the main codes are subsequently applied whenever the codes are used thereafter. These steps are repeated with each successive code pair having the same separation as the first code pair, e.g. both incremented by same amount until all codes have been calibrated. In this manner having the phase separation between all code pairs forced to the same value.

Abstract: A system that incorporates teachings of the subject disclosure may include, for example, a method for identifying a spectral region in a radio frequency spectrum, determining a signal strength of the spectral region, determining a correlation factor by correlating the signal strength of the spectral region, detecting according to the correlation factor interference in the spectral region, generating coefficient data to substantially suppress the interference in the spectral region, configuring a filter according to the coefficient data to substantially suppress the interference in the spectral region and produce a digital filtered signal, and transmitting the digital filtered signal to a base station. Other embodiments are disclosed.

Abstract: In one embodiment, a communication device comprises a differential encoder to receive data for transmission and encode the data for transmission using a set of codes that, when processed by the differential encoder, place the differential encoder in a known state and generate uncorrelated output sequences.

Abstract: A system that incorporates teachings of the subject disclosure may include, for example, a method for scanning a radio frequency spectrum for an available frequency band, selecting an available frequency band in the radio frequency spectrum even if the available frequency band is affected by radio frequency interference, measuring a signal strength in portions of the available frequency band, correlating the signal strength of each portion to generate a correlation factor, detecting radio frequency interference in the available frequency band according to the correlation factor, and generating tuning coefficient data to cause the filter apparatus to substantially suppress the radio frequency interference in the available frequency band. Other embodiments are disclosed.

Abstract: A modulator and demodulator pair may switch configurations without introducing errors as a result of the switch. Different configurations may, for example, correspond to different symbol rates and/or different amounts of controlled inter-symbol interference (ISI) introduced to the transmitted signal. For example, a first configuration may use be a near-zero ISI configuration (e.g., using Nyquist signaling) and a second configuration may introduce a significant (e.g., amount that would result in errors above a desired threshold if demodulation relied on symbol-by-symbol slicing) but controlled amount of ISI (e.g., using partial response or faster-than-Nyquist-rate signaling). Switching between modulator/demodulator configurations may be needed to maintain a stable link in the case of dynamic channels. At any given time, a modulator and demodulator pair may, for example, switch to a configuration that provides maximal throughput for the current channel conditions.

Abstract: A method and system for receiving and decoding horizontally encoded MIMO-OFDM transmissions with improved efficiency. In one embodiment, MIMO decoding is performed on each of the extracted separate tones of a MIMO-OFDM signal to extract and demodulate frequency domain symbols of the first layer corresponding to one or more code blocks. For each code block of the first layer that passes an error check, corresponding portions of the second layer are decoded using SIMO decoding.

Abstract: A method in a wireless communication terminal (103), including receiving a radio resource allocation comprising a plurality of sub-carriers that is a subset of available sub-carriers, wherein the available sub-carriers include a DC sub-carrier, wherein the DC sub-carrier and all but one edge-most sub-carrier of the plurality of sub-carriers are designated for transmission if the DC sub-carrier is between any two sub-carriers of the allocation, and all of the sub-carriers except the DC sub-carrier from the plurality of sub-carriers are designated for transmission if the DC sub-carrier is not between any two sub-carriers of the allocation.

Abstract: In an embodiment, a transmitter includes first and second transmission paths. The first transmission path is configurable to generate first pilot clusters each including a respective first pilot subsymbol in a first cluster position, and the second transmission path is configurable to generate second pilot clusters each including a respective second pilot subsymbol in a second cluster position such that a vector formed by the first pilot subsymbols is orthogonal to a vector formed by the second pilot subsymbols. For example, where such a transmitter transmits simultaneous orthogonal-frequency-division-multiplexed (OFDM) signals (e.g., MIMO-OFDM signals) over respective channels that may impart inter-carrier interference (ICI) to the signals due to Doppler spread, the pattern of the pilot symbols that compose the pilot clusters may allow a receiver of these signals to use a recursive algorithm, such as a Vector State Scalar Observation (VSSO) Kalman algorithm, to estimate the responses of these channels.