Situne Corporation

Mahdi Khoshgard

Vahid Mesgarpour Toosi

Marzieh Veyseh

Saeid Mehrmanesh

Yahya Tousi

Approaches provide for processing a communications signal, such as a wideband communications signal. For example, a communications signal can be received at an access device, such as a cable modem or a wireless transceiver/radio. The access device can include components operable to process the communications signal to enable access to, for example, video, data, voice, high-speed Internet services. At least some of the components include an echo cancellation component among other components to cancel interference (e.g., ACI, ALI). For example, the echo cancellation component can use trained filters and samples of the upstream signal, echoed samples of the transmitted signal, feedback signals of the echoed signal, etc., to estimate one or more types of interference. Thereafter, the estimated interference can be used to cancel interference at the access device.

Self interference cancellation for high performance transceivers

Approaches provide for determining spectral information for a communications signal, such as a wideband communications signal. For example, a communications signal (e.g., a wideband signal) is received at a set of analog-to-digital converters (ADCs). The output of the ADCs is divided into a set of segments. A center frequency for each segment is determined based on the segment bandwidth and a number of segments in the set. The segments can be filtered, buffered, and analyzed using at least one digital signal processing technique (e.g., Fast Fourier Transform (FFT) technique to generate a representation of the segments in the frequency domain. Thereafter, the spectrum of frequency components (i.e., the frequency-domain representation) of the segments can be used to determine the power spectral density of the communications signal for different resolutions based on a resolution mode of the system or other criteria of the system.

Spectrum monitoring

Approaches provide for calibrating high speed analog-to-digital converters (ADCs). For example, a calibration signal can be applied to parallel ADCs. The output of the parallel ADCs can be analyzed using a set of filtering components configured to at least filter image components and cause a phase shift in the output signals. One or more delay adjustment components can cause a delay to at least the output of the parallel ADCs and the set of filtering components. A cross-correlating component can be utilized to cross-correlate the output of the parallel ADCs with an output signal of at least one filtering component of the set of filtering components and an output signal of at least one delay adjustment component of the set of delay adjustment components. A conversion component determines polar coordinates from rectangular coordinates from the output of the cross-correlating component. Thereafter, a time-offset and gain estimator component can determine one of gain error calibration data or time-offset calibration data based at least in part on an output signal of the conversion component, which can be stored and/or used to calibrate individual time-interleaved ADCs.

Time error and gain offset estimation in interleaved analog-to-digital converters

Approaches provide for calibrating high speed analog-to-digital converters (ADCs). For example, a calibration signal can be applied to parallel ADCs. The output of the parallel ADCs can be analyzed using a gradient-based optimization approach or other such optimization approach to determine optimized gain error calibration data to compensate for gain mismatch in and between individual parallel time-interleaved ADCs and to determine time-offset calibration data to compensate for timing errors in and between individual parallel time-interleaved ADCs. For example, once a calibration signal is applied to an ADC, the output of the ADC can be analyzed to determine a spectrum of the calibration signal. One or more images (e.g., phasors) of the spectrum can be determined and used to determine initial values of the optimization. Thereafter, the optimization approach can be utilized to determine optimized gain error calibration data and optimized time-offset calibration data, which can be stored and/or used to calibrate individual time-interleaved ADCs.

Offset calibration of analog-to-digital converters using a spectrum analyzer

The present disclosure relates to a method and system for tone signal removal from a noisy signal that includes a desired signal in combination with the tone signal. The method and system provides an artificial or estimated undesired tone signal with the same frequency as the undesired tone signal, which, in combination with an estimated phasor, is available to filter or subtract a noisy component from the noisy signal and to provide the filtered or clean desired signal.

Tone removal for digital circuits

The present disclosure relates to implementations of a method and a system for calibrating the system that includes analog-to-digital converters (ADCs). The method, performed on the system's corresponding components include, providing, from a signal generator, a first signal during a calibration mode. Parallel ADCs provide ADC outputs associated with the first signal. First parallel filters provide derivative signals associated with the ADC outputs. Second and third parallel filters provide first and second band-stop filtered signals associated with the ADC outputs and the derivative signals, respectively. The disclosure includes multiplying the first and the second band-stop filtered signals and selecting a portion of the multiplied signals that are accumulated for storage. The system incorporating these components performing these features is, accordingly, calibrated.

Calibration of high speed ananlog-to-digital converters

A system and method are provided for calibrating the IQ-imbalance in a low-IF receiver. A Test Signal can be generated in a mirror frequency and conveyed to the receiver. The power of the signal produced in the receiver from the conveyed Test Signal can be measured. In the absence of an IQ-imbalance, the Test Signal can be completely eliminated in the receiver and the corresponding measured power of the produced signal can be minimized. Accordingly, a two dimensional algorithm is described for calibrating a receiver and correcting the IQ-imbalance by adjusting the phase and gain difference between the I and Q channels in the receiver based on the measured power of the signal produced in the receiver.

Mirror signal IQ-imbalance correction

An example method includes extracting calibration coefficients of each stage of a pipeline analog-to-digital convertor (ADC). The calculation of the corrected digital output of the pipeline ADC can be based on the digital output of each pipeline stage and the estimated calibration coefficient of the corresponding stage. Therefore, a relaxed design of the operational amplifier and sizing of capacitors in a high speed asynchronous ADC can be achieved.

Calibration of high speed asynchronous convertor

Systems and methods are described for synchronizing a receiver to a received signal and other signal processing approaches and/or components associated with the receiver. For example, a signal (e.g., a radio frequency (RF) signal such as a broadband TV signal in UHF and VHF frequencies) can be received at a receiver. Before the signal is provided to other components of the receiver, the signal can be processed in a component of the receiver commonly known as the digital front-end, where such processing can include amongst others, various synchronization and acquisition techniques.

Synchronization and acquisition in radio communication systems

Systems and methods are described for the implementation of a full band cable receiver by using a combination of tuners (e.g., ultra-low power Tuners) and Analog-to-Digital Converters (ADCs) to attain the goal of digitization with reduced power and/or cost. The full-band capture cable receiver can overcome the constraints of conventional cable receiver systems and deliver multiple channels, thereby allowing operators to provide consumers with an increased number of services.

Full band cable receiver

A system and method is provided for estimating the channel in OFDM transmission with inter-carrier interference (ICI). A channel in a data subcarrier in a subchannel shared between pilot subcarriers and data subcarriers can be estimated by performing interpolation based on estimated channels in pilot subcarriers in the same OFDM symbol as the subcarrier, such as through spline interpolation. A second estimate of the channel in the subcarrier can be produced by averaging an estimate of the channel in a subcarrier in the subchannel in a previous OFDM symbol and an estimate of the channel in a subcarrier in the subchannel in a succeeding OFDM symbol. A third estimate of the channel in the subcarrier can be produced through a linear combination of the first estimate and the second estimate. The channel in data subcarriers can be estimated through a weighted sum of the channel in nearest subcarriers.

Channel estimation in OFDM transmission system and method

Systems and methods are described for the implementation of a receiver that includes a channel estimation block that uses known pilots to estimate the value of channel gain and phase at data subcarrier indexes. Time interpolation as well as an auto regression filter can be to estimate the channel gain and phase at the 'missing' pilot indexes as well as frequency interpolation to estimate the value of the channel at data subcarrier indexes.

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Los Gatos, CA, United States of America

Mahdi Khoshgard