An analog-to-digital conversion circuit includes; a first analog-to-digital converter (ADC), a second ADC and a third ADC collectively configured to perform conversion operations according to a time-interleaving technique, and a timing calibration circuit configured to calculate correlation values and determine differences between the correlation values using first samples generated by the first ADC, second samples generated by the second ADC, and third samples generated by the third ADC during sampling periods, wherein the timing calibration circuit is further configured to control a phase of a clock signal applied to the second ADC in response to a change in absolute value related to the differences generated during the sampling periods.

A pipelined analog-to-digital converter and an output calibration method for the same. The pipelined analog-to-digital converter introduces an error calibration mechanism on the basis of traditional pipelined analog-to-digital converters through a control module, an equivalent gain error extraction module, an error storage module and a coding reconstruction module to compensate for gain errors and setup errors caused by operational amplifiers in a pipelined conversion module, so that the analog-to-digital conversion accuracy is improved, and requirements for the gain and bandwidth of the operational amplifier are relaxed, which can effectively reduce the power consumption of the analog-to-digital converter and the complexity of the corresponding analog circuit; a curve fitting method is adopted to obtain an ideal output sequence and then calculate errors; meanwhile, extraction and calibration of equivalent gain errors are all done in digital ways, and therefore accuracy thereof is high.

A calibrating device can mitigate the static mismatch error of a digital-to-analog converter (DAC), and includes a digital code generating circuit, the DAC, an analog-to-digital converter (ADC), a filter circuit, an indicating circuit, and a statistical circuit. The digital code generating circuit generates a digital code of N digital codes. The DAC generates an analog signal corresponding to one of N signal levels according to the digital code. The ADC generates a digital signal according to the analog signal. The filter circuit generates a gradient value according to the difference between the digital code and the digital signal. The indicating circuit generates a selection signal according to the digital code. The statistical circuit learns from the selection signal that the gradient value is corresponding to a K.sup.th digital code of the N digital codes, and determines whether the K.sup.th digital code should be adjusted according to the gradient value.

A calibration circuit, including: a signal generator circuit configured to generate a modulated analog input signal, which is based on a digital input word that is modulated; an Analog-to-Digital Converter (ADC) configured to convert an analog reference signal to a digital calibration word, wherein the analog reference signal is a low-pass-filtered version of the analog input signal generated by the signal generator circuit; and a feedback circuit configured to output the digital input word by adjusting the digital calibration word depending on a digital feedback signal, which is based on a modulated version of the analog reference signal, wherein the signal generator circuit, the ADC, and the feedback circuit are provided on a same chip.

An N-channel interleaved Analog-to-Digital Converter (ADC) has a variable delay added to each ADC's input sampling clock. The variable delays are each programmed by a Successive-Approximation-Register (SAR) during calibration to minimize timing skews between channels. Each channel receives a sampling clock with a different phase delay. The sampling clocks are overlapping multi-phase clocks rather than non-overlapping. Overlapping the multi-phase clocks allows the sampling pulse width to be enlarged, providing more time for the sampling switch to remain open and allow analog voltages to equalize through the sampling switch. Higher sampling-clock frequencies are possible than when non-overlapping clocks are used. The sampling clock is boosted in voltage by a bootstrap driver to increase the gate voltage on the sampling switch, reducing the ON resistance. Sampling clock and component timing skews are reduced to one LSB among all N channels.

An N-channel interleaved Analog-to-Digital Converter (ADC) has a variable delay added to each ADC's input sampling clock. The variable delays are each programmed by a Successive-Approximation-Register (SAR) during calibration to minimize timing skews between channels. In each channel the ADC output is filtered, and a product derivative correlator generates a product derivative factor for correlation to two adjacent ADC channels. A matrix processor arranges the product derivative factors from the product derivative correlators into a matrix that is multiplied by a correlation matrix. The correlation matrix is a constant generated from an N×N shift matrix. The matrix processor outputs a sign-bit vector. Each bit in the sign-bit vector determines when tested SAR bits are set or cleared to adjust a channel's variable delay. Sampling clock and component timing skews are reduced to one LSB among all N channels.

A system and method for calibrating a time-interleaved digital-to-analog converter (DAC). A calibration signal generator generates calibration data, and a time-interleaved DAC converts the calibration data to an analog calibration signal. An observation analog-to-digital converter (ADC) samples, and quantizes, the analog calibration signal filtered by an anti-alias filter. A mismatch estimation block estimates a frequency response mismatch between the sub-DACs and generates a sub-DAC mismatch correction factor based on an output of the observation ADC. The calibration signal generator applies the sub-DAC mismatch correction factor to the calibration data. The mismatch estimation block may estimate a DC offset mismatch between the sub-DACs based on the output of the observation ADC and generates a DC offset correction factor, and the calibration signal generator applies the DC offset correction factor to the calibration data.

Disclosed is a calibration method of a capacitor array type successive approximation register analog-to-digital converter, comprising: obtaining an actual weight value of capacitors of a target bit and an error code between the actual weight value and an ideal weight value of the capacitors of the target bit; calibrating an output code of the SAR ADC to be calibrated with the error code by corresponding addition or subtraction to obtain a final calibrated output code. The calibration method breaks through the requirement that non-binary weights must meet the redundancy, and can realize a weight calibration in a traditional binary ADC and a digital calibration by simple addition and subtraction on the basis of the original code obtained by an analog-to-digital conversion, thus effectively avoiding the error problem in the traditional technology, increasing the calibration precision and accuracy, reducing the circuit complexity and calculation complexity caused by the non-binary weights calibration.

The present invention discloses a digital-to-analog conversion apparatus having signal calibration mechanism. A DAC circuit includes conversion circuits to generate an output analog signal and an echo-canceling analog signal. An echo transmission circuit performs signal processing on an echo path to generate an echo signal. An echo calibration circuit includes odd and even calibration circuits to perform mapping according to offset tables and perform processing according to response coefficients on odd and even input parts of an input digital signal to generate odd and even calibration parts of an echo-canceling calibration signal. A calibration parameter calculation circuit generates offsets according to an error signal between the echo signal and the echo-canceling calibration signal and path information related to the echo calibration circuit. The echo calibration circuit makes the coefficients converge according to the error signal and pseudo noise transmission path information, and updates the offset tables according to the offset.

A system includes a first digital-to-time converter (DTC) adapted to receive a first DTC code and a first clock signal. The first DTC provides an output clock signal. The system includes a calibration DTC adapted to receive a calibration DTC code and a second clock signal. The calibration DTC provides a calibration output signal. The system includes a latch comparator which provides outputs indicative of which of the output clock signal and the calibration output signal is received first. The system includes an average computation module which provides an average value of the outputs of the latch comparator. The system includes a digital controller adapted to receive the average value. The digital controller provides the DTC code and the calibration DTC code.