An analog to digital converter (ADC) device includes ADC circuits, a calibration circuit and a controlling circuit. The ADC circuits are configured to generate first quantized outputs according to clock signals. The calibration circuit is configured to perform at least one error operation according to the first quantized outputs to generate second quantized outputs, and is configured to analyze time difference information of the clock signals according to the second quantized outputs to generate adjustment signals. The controlling circuit is configured to analyze the first quantized outputs to generate at least one control signal to the calibration circuit, wherein the at least one control signal is configured to control the calibration circuit to selectively perform the at least one error operation and selectively analyze the time difference information of the clock signals.

A method uses a distributed data acquisition system with multiple, physically unconnected, data acquisition units, that can be in wireless communication with a remote host, to timestamp measurement data with sub-microsecond time base accuracy of sampling clock relative to an absolute timeframe. A current absolute time is derived from messages received from a satellite radio beacon positioning system (GPS). Measurement data is sampled by each unit at a specified sampling rate. Using hardware logic, batches of sampled data are associated with corresponding timestamps representing the absolute time at which the data was sampled. Data and timestamps may be transmitted to the host. A time offset bias is compensated by comparing timestamps against a nominal time based on start time and nominal sampling rate. The sampling clock rate may be disciplined using time pulses from the GPS receiver. An initial start of data sampling by all units can also be synchronized.

Described are apparatus and methods to calibrate and align multiple high-speed clock domains. A system includes at least two clock domains, a launch circuit connected to each of the at least two domains, and a calibration circuit. Each clock domain including a resettable device having a local reset retime clock. The launch circuit aligns a reset pulse with the local reset retime clock by using a launch clock from one of the domains, where the reset pulse is incoherent with respect to the domains, adjusts a delay of the launch clock to control a launch time of the reset pulse, and sends the reset pulse based on the delayed launch clock. The calibration circuit samples a local reset retime delayed clock to generate a readback signal. The launch circuit and the calibration circuit iterate through selected delays until safe arrival timing is indicated from each readout.

This application discloses a clock synchronization system, including a quantum control processor (QCP) and N digital/analog mutual conversion devices, each digital/analog mutual conversion device including a frequency conversion module and a signal synchronization module that includes a D flip-flop (DFF). The QCP generates a global synchronization signal and reference clock signals; and transmits the global synchronization signal and a reference clock signal to the frequency conversion module and transmits the global synchronization signal to the signal synchronization module of each conversion device. The frequency conversion module performs frequency conversion processing on the reference clock signal to obtain a target clock signal, and generates a signal synchronization instruction according to the global synchronization signal; and transmits the signal synchronization instruction and the target clock signal to the signal synchronization module. The signal synchronization module performs, based on the global synchronization signal, signal synchronization on the target clock signal through the DFF.

An error correction method and a time-interleaved analog-to-digital converter (TIADC) are provided. The method is applied to a TIADC that includes a plurality of analog-to-digital converters (ADCs), and the method includes: determining whether a current value of a codeword of a first ADC in the plurality of ADCs is within a preset range; when the current value of the codeword of the first ADC is not within the preset range, adjusting a plurality of codewords that are in a one-to-one correspondence with the plurality of ADCs; and controlling a clock frequency division circuit to generate, by using a plurality of adjusted codewords, a plurality of sampling clocks that are in a one-to-one correspondence with the plurality of ADCs. In embodiments of this application, a sampling time-period skew existing between ADCs may be adjusted by adjusting codewords corresponding to the ADCs.

Analog gain correction circuitry and analog switching clock edge timing correction circuitry can provide coarse correction of interleaving errors in radio-frequency digital-to-analog converters (RF DACs), such as may be used in 5G wireless base stations. The analog correction can be supplemented by digital circuitry configured to “pre-cancel” an interleaving image by adding to a digital DAC input signal a signal equal and opposite to an interleaving image created by the interleaving DAC, such that the interleaving image is effectively mitigated. Error correction control parameters can be periodically adjusted for changes in temperature by a controller coupled to an on-chip temperature sensor. A model useful for understanding the sources of error in interleaving DACs is also described.

According to the one embodiment, a semiconductor circuit includes: an analog-to-digital conversion circuit including a first analog-to-digital converter configured to sample at least one first sampling signal regarding an input signal based on a first clock, and a second analog-to-digital converter configured to sample at least one second sampling signal regarding the input signal based on a second clock shifted from the first clock by a first time; and a first calibration circuit configured to calibrate at least one timing of the first clock and the second clock based on a calculation result of a moving average of the first sampling signal and the second sampling signal.

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. An auto-correlator generates a sign of a correlation error for a pair of ADC digital outputs. SAR bits are tested with the correlation sign bit determining when to add or subtract SAR bits. First all pairs are calibrated in a first level of a binary tree of mux-correlators. Then skews between remote pairs and groups are calibrated in upper levels of the binary tree using auto-correlators with inputs muxed from groups of ADC outputs input to the binary tree of mux-correlators. The binary tree of mux-correlators can include bypasses for odd and non-binary values of N. Sampling clock and component timing skews are reduced to one LSB among both adjacent channels and remote channels.

A time-interleaved analog-to-digital converter (TIADC) operates in a first mode or a second mode and includes M analog-to-digital converters (ADCs), a reference ADC, a digital correction circuit, and a control circuit. The M ADCs sample an input signal according to M enable signals to generate M digital output codes. The reference ADC samples the input signal according to a reference enable signal to generate a reference digital output code. The digital correction circuit corrects the M digital output codes to generate M corrected digital output codes. The control circuit generates the M enable signals and the reference enable signal according to a clock. The control circuit outputs the M corrected digital output codes in turn but does not output the reference digital output code in the first mode and randomly outputs the M corrected digital output codes and the reference digital output code in the second mode.

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.