Abstract: An ADC can include a plurality of time-interleaved ADCs to increase the overall sampling rate of the ADC. Such an ADC can have interleaving errors, since the time-interleaved ADCs in the ADC are not always perfectly matched. One way to calibrate for these mismatches is by observing the digital output signals of the time-interleaved ADCs in the background, or more broadly, without knowledge of the input signal to the ADC (often referred to as “blind” calibration). Due to the nature of these calibrations, the performance of the calibration would significantly degrade when the input signal has certain problematic input conditions, such as a certain coherent input frequency. To address this issue, the data being used for calibration of interleaving errors can go through a qualifying process to assess whether to update error estimates based on the data.

Abstract: To address non-linearity, an on-chip linearization scheme is implemented along with an analog-to-digital converter (ADC) to measure and correct/tune for non-linearities and/or other non-idealities of the signal path having the ADC. The on-chip linearization scheme involves generating one or more test signals using an on-chip digital-to-analog converter (DAC) and providing the one or more test signals as input to the signal path to be linearized, and estimating non-linearity based on the one or more test signals and the output of the ADC. Test signals can include single-tone signals, multi-tone signals, and wideband signals spread over a range of frequencies. A time-delayed interleaving clocking scheme can be used to achieve a higher data rate for coefficient estimation without having to increase the sample rate of the ADC.

Abstract: To address non-linearity, an on-chip linearization scheme is implemented along with an analog-to-digital converter (ADC) to measure and correct/tune for non-linearities and/or other non-idealities of the signal path having the ADC. The on-chip linearization scheme involves generating one or more test signals using an on-chip digital-to-analog converter (DAC) and providing the one or more test signals as input to the signal path to be linearized, and estimating non-linearity based on the one or more test signals and the output of the ADC. Test signals can include single-tone signals, multi-tone signals, and wideband signals spread over a range of frequencies. A time-delayed interleaving clocking scheme can be used to achieve a higher data rate for coefficient estimation without having to increase the sample rate of the ADC.

Abstract: A time-interleaved analog-to-digital converter (ADC) having M ADCs can increase the sampling speed several times compared to the sampling speed of just one ADC. Some time-interleaved ADCs randomize the order of the M ADCs sampling the analog input signal to improve dynamic performance. Randomization causes the output data of the M ADCs to be valid at randomized time instants. When the output data is sampled using a rising edge of a fixed clock, the output data can be valid just before, valid right at, or only valid for a short period of time after, the rising edge. Therefore, the setup or hold time can be very short. To address this issue, information regarding the randomized selection of an ADC is used to control the sampling occurring in the fixed clock domain and avoid the short setup or hold time.

Abstract: Many systems implement calibration schemes to measure and correct for the non-idealities. Such systems can be complex, which makes them impractical to implement since the cost can potentially outweigh the benefits of the calibration scheme. To implement efficient and effective calibration, non-idealities or errors of a system are detected, in foreground or in background, in a piecewise fashion based on, e.g., correlations of an output signal with an uncorrelated random signal, where the correlation results are processed separately for different open intervals of an error signal. Second order and third order correction terms can be easily determined based on three open intervals. In various embodiments, the calibration scheme can detect and correct for linear errors, (linear and non-linear) memory/frequency dependent errors, static nonlinearity errors, Hammerstein-style non-linearity errors, and Wiener-style non-linearity errors (cross-terms).

Abstract: Many systems implement calibration schemes to measure and correct for the non-idealities. Such systems can be complex, which makes them impractical to implement since the cost can potentially outweigh the benefits of the calibration scheme. To implement efficient and effective calibration, non-idealities or errors of a system are detected, in foreground or in background, in a piecewise fashion based on, e.g., correlations of an output signal with an uncorrelated random signal, where the correlation results are processed separately for different open intervals of an error signal. Second order and third order correction terms can be easily determined based on three open intervals. In various embodiments, the calibration scheme can detect and correct for linear errors, (linear and non-linear) memory/frequency dependent errors, static nonlinearity errors, Hammerstein-style non-linearity errors, and Wiener-style non-linearity errors (cross-terms).

Abstract: A time-interleaved analog-to-digital converter (ADC) having M ADCs can increase the sampling speed several times compared to the sampling speed of just one ADC. Some time-interleaved ADCs randomize the order of the M ADCs sampling the analog input signal to improve dynamic performance. Randomization causes the output data of the M ADCs to be valid at randomized time instants. When the output data is sampled using a rising edge of a fixed clock, the output data can be valid just before, valid right at, or only valid for a short period of time after, the rising edge. Therefore, the setup or hold time can be very short. To address this issue, information regarding the randomized selection of an ADC is used to control the sampling occurring in the fixed clock domain and avoid the short setup or hold time.

Abstract: Analog-to-digital converters (ADCs) can have errors which can affect their performance. To improve the performance, many techniques have been used to compensate or correct for the errors. When the ADCs are being implemented with sub-micron technology, ADCs can be readily and easily equipped with an on-chip microprocessor for performing a variety of digital functions. The on-chip microprocessor and any suitable digital circuitry can implement functions for reducing those errors, enabling certain undesirable artifacts to be reduced, and providing a flexible platform for a highly configurable ADC. The on-chip microprocessor is particularly useful for a randomized time-interleaved ADC. Moreover, a randomly sampling ADC can be added in parallel to a main ADC for calibration purposes. Furthermore, the overall system can include an efficient implementation for correcting errors in an ADC.

Abstract: Analog-to-digital converters (ADCs) can have errors which can affect their performance. To improve the performance, many techniques have been used to compensate or correct for the errors. When the ADCs are being implemented with sub-micron technology, ADCs can be readily and easily equipped with an on-chip microprocessor for performing a variety of digital functions. The on-chip microprocessor and any suitable digital circuitry can implement functions for reducing those errors, enabling certain undesirable artifacts to be reduced, and providing a flexible platform for a highly configurable ADC. The on-chip microprocessor is particularly useful for a randomized time-interleaved ADC. Moreover, a randomly sampling ADC can be added in parallel to a main ADC for calibration purposes. Furthermore, the overall system can include an efficient implementation for correcting errors in an ADC.

Abstract: Analog-to-digital converters (ADCs) can have errors which can affect their performance. To improve the performance, many techniques have been used to compensate or correct for the errors. When the ADCs are being implemented with sub-micron technology, ADCs can be readily and easily equipped with an on-chip microprocessor for performing a variety of digital functions. The on-chip microprocessor and any suitable digital circuitry can implement functions for reducing those errors, enabling certain undesirable artifacts to be reduced, and providing a flexible platform for a highly configurable ADC. The on-chip microprocessor is particularly useful for a randomized time-interleaved ADC. Moreover, a randomly sampling ADC can be added in parallel to a main ADC for calibration purposes. Furthermore, the overall system can include an efficient implementation for correcting errors in an ADC.

Abstract: Analog-to-digital converters (ADCs) can have errors which can affect their performance. To improve the performance, many techniques have been used to compensate or correct for the errors. When the ADCs are being implemented with sub-micron technology, ADCs can be readily and easily equipped with an on-chip microprocessor for performing a variety of digital functions. The on-chip microprocessor and any suitable digital circuitry can implement functions for reducing those errors, enabling certain undesirable artifacts to be reduced, and providing a flexible platform for a highly configurable ADC. The on-chip microprocessor is particularly useful for a randomized time-interleaved ADC. Moreover, a randomly sampling ADC can be added in parallel to a main ADC for calibration purposes. Furthermore, the overall system can include an efficient implementation for correcting errors in an ADC.

Abstract: Analog-to-digital converters (ADCs) can have errors which can affect their performance. To improve the performance, many techniques have been used to compensate or correct for the errors. When the ADCs are being implemented with sub-micron technology, ADCs can be readily and easily equipped with an on-chip microprocessor for performing a variety of digital functions. The on-chip microprocessor and any suitable digital circuitry can implement functions for reducing those errors, enabling certain undesirable artifacts to be reduced, and providing a flexible platform for a highly configurable ADC. The on-chip microprocessor is particularly useful for a randomized time-interleaved ADC. Moreover, a randomly sampling ADC can be added in parallel to a main ADC for calibration purposes. Furthermore, the overall system can include an efficient implementation for correcting errors in an ADC.

Abstract: Analog-to-digital converters (ADCs) can have errors which can affect their performance. To improve the performance, many techniques have been used to compensate or correct for the errors. When the ADCs are being implemented with sub-micron technology, ADCs can be readily and easily equipped with an on-chip microprocessor for performing a variety of digital functions. The on-chip microprocessor and any suitable digital circuitry can implement functions for reducing those errors, enabling certain undesirable artifacts to be reduced, and providing a flexible platform for a highly configurable ADC. The on-chip microprocessor is particularly useful for a randomized time-interleaved ADC. Moreover, a randomly sampling ADC can be added in parallel to a main ADC for calibration purposes. Furthermore, the overall system can include an efficient implementation for correcting errors in an ADC.

Abstract: A hydrokinetic turbine system, including a plurality of hydrokinetic turbines is installed on a bed of a body of water. Each turbine has a shroud with a forward entrance portion and rear exit portion. The shroud includes a propeller disposed in a middle portion thereof. An inner surface of the shroud includes a plurality of rifling vanes formed therein to induce water entering the forward entrance portion to rotate in a vortex-like fashion. A plurality of pre-spin guard blades disposed adjacent the forward entrance portion also induce rotation of water and serve to provide a barrier preventing objects from passing into the forward entrance portion. A plurality of stabilizers extending from an exterior surface of the shroud that position the forward entrance portion in the direction of current flow.

Abstract: A hydrokinetic turbine system, including a plurality of hydrokinetic turbines is installed on a bed of a body of water. Each turbine has a shroud with a forward entrance portion and rear exit portion. The shroud includes a propeller disposed in a middle portion thereof. An inner surface of the shroud includes a plurality of rifling vanes formed therein to induce water entering the forward entrance portion to rotate in a vortex-like fashion. A plurality of pre-spin guard blades disposed adjacent the forward entrance portion also induce rotation of water and serve to provide a barrier preventing objects from passing into the forward entrance portion. A plurality of stabilizers extending from an exterior surface of the shroud that position the forward entrance portion in the direction of current flow.