A digital signal generation assumes that a base frequency (the frequency with which the primitive phase angles are specified relative to) is equal to the carrier frequency for all relevant times. But this causes errors in the digital signals output to each array element transducer. Thus, it is necessary for the development of a signal generation system that is capable of producing a digital signal using the free selection of amplitude and phase. This is used to produce a substantially error-free signal that preserves the amplitude and phase relative to a constant base frequency while allowing the carrier frequency to vary.

Calibration of continuous-time (CT) residue generation systems can account and compensate for mismatches in magnitude and phase that may be caused by fabrication processes, temperature, and voltage variations. In particular, calibration may be performed by providing one or more known test signals as an input to a CT residue generation system, analyzing the output of the system corresponding to the known input, and then adjusting one or more parameters of a forward and/or a feedforward path of the system so that the difference in transfer functions of these paths may be reduced/minimized. Calibrating CT residue generation systems using test signals may help decrease the magnitude of the residue signals generated by such systems, and, consequently, advantageously increase an error correction range of such systems or of further stages that may use the residue signals as input.

A digital signal generation assumes that a base frequency (the frequency with which the primitive phase angles are specified relative to) is equal to the carrier frequency for all relevant times. But this causes errors in the digital signals output to each array element transducer. Thus, it is necessary for the development of a signal generation system that is capable of producing a digital signal using the free selection of amplitude and phase. This is used to produce a substantially error-free signal that preserves the amplitude and phase relative to a constant base frequency while allowing the carrier frequency to vary.

A photonic random signal generator includes an incoherent optical source configured to generate an optical noise signal, a filter configured to generate a filtered optical noise signal using the optical noise signal, a coupler, a photodetector, a filter, and a limiter. The coupler couples the filtered optical noise signal and a delayed version of the filtered optical noise signal to generate a first coupled signal and a second coupled signal. The photodetector generates an output signal representative of a phase difference between the filtered optical noise signal and the delayed version of the filtered optical noise signal using the first coupled signal and the second coupled signal. The filter filters the output signal representative of the phase difference to generate an analog random signal. The limiter thresholds the analog random signal based on a clock signal, to generate a digital random signal.

Mechanisms for reducing or eliminating a quantization error caused by a quantizer of a continuous-time (CT) residue generation system are disclosed. In particular, systems and methods described herein are based on using a dither generation and injection circuit that can perform a high-pass filtering of the additive dither signal (i.e., a high-pass shaped dither signal). Using high-pass shaped dither signals is expected to improve quantizer linearity without significantly reducing the available error correction range. The applied dither may be particularly effective at minimizing signal-dependent distortion in ADC output spectrum caused by the quantizer when the quantization error cancellation accuracy may be insufficient.

Analog circuits are often non-linear, and the non-linearities can hurt performance. Designers would trade off power consumption to achieve better linearity. An efficient and effective calibration technique can address the non-linearities and reduce the overall power consumption. A dither signal injected to the analog circuit can be used to expose the non-linear behavior in the digital domain. To detect the non-linearities, a counting approach is applied to isolate non-linearities independent of the input distribution. The approach is superior to and different from other approaches in many ways.

Quantisation methods are provided which employ dither techniques to reduce the noise penalty in certain circumstances whilst still removing noise modulation. One method relates to reducing the wordwidth of audio by one bit, while another method relates to burying one bit of data in a pair of signal samples.

Digital to analog conversion generates an analog output corresponding to a digital input by controlling unit elements or cells using data bits of the digital input. The unit elements or cells individually make a contribution to the analog output. Due to process, voltage, and temperature variations, the unit elements or cells may have mismatches and/or errors. The mismatches and/or errors can degrade the quality of the analog output. To extract the mismatches and/or errors, a transparent dither can be used. The mismatches and/or errors can be extracted by observing the analog output, and performing a cross-correlation of the observed output with a switching bit stream of the dither. Once extracted, the unit elements or cells can be adjusted accordingly to reduce the respective mismatches and/or errors.

An apparatus including analog-to-digital conversion (ADC) circuitry is disclosed. The apparatus includes a plurality of comparators susceptible to offset variation and a shuffler circuit configured to shuffle input sources to the respective comparators. Feedback circuitry is also included and is configured and arranged with the ADC circuitry to detect offset variation in the outputs of each comparators for the shuffled inputs, relative to outputs of the plurality of comparators and compensate for the offset variation in the comparators based on the offset differences between the respective comparators.

A digital signal generation assumes that a base frequency (the frequency with which the primitive phase angles are specified relative to) is equal to the carrier frequency for all relevant times. But this causes errors in the digital signals output to each array element transducer. Thus, it is necessary for the development of a signal generation system that is capable of producing a digital signal using the free selection of amplitude and phase. This is used to produce a substantially error-free signal that preserves the amplitude and phase relative to a constant base frequency while allowing the carrier frequency to vary.