Time varying quantization-based linearity enhancement of signal converters and mixed-signal systems

A signal-linearization system for reducing nonlinear distortions in a digitized signal generated by an analog-to-digital converter (ADC) when converting an analog input signal from analog to digital form, the system comprising:

• a signal adder adding a dither waveform to the analog input signal, the dither waveform being substantially uncorrelated with the analog input signal and having a signal level that is approximately equal to or greater than a maximum signal level of the analog input signal;
• an ADC including sample-and-hold (S/H) circuitry and quantizer circuitry, the ADC converting the analog input signal with the added dither waveform into a digitized signal, the dither waveform operating to suppress nonlinear distortions attributed to the quantizer circuitry;
• a linearizer processor performing nonlinear equalization (NLEQ) on the digitized signal to suppress nonlinear distortions attributed to the S/H circuitry;
• and
• a dither waveform removal module removing a digital counterpart of the dither waveform from the digitized signal.

A signal-linearization system for reducing nonlinear distortions in a digitized signal generated by an analog-to-digital converter (ADC) when converting an analog input signal from analog to digital form, the system comprising:

• means for providing an analog input signal to each ADC of a plurality of ADCs operating in parallel;
• a plurality of analog signal adders, each signal adder being in communication with one of the ADCs, each signal adder combining a dither waveform to the analog input signal provided to the ADC with which that signal adder is in communication, each dither waveform added to one of the analog input signals being adapted to suppress nonlinear distortions attributed to quantizer circuitry of the ADC receiving that analog input signal, each dither waveform being substantially uncorrelated with that one analog input signal to which that dither waveform is added, and each dither waveform having a signal level that is approximately equal to or greater than a maximum signal level of that one analog input signal to which that dither waveform is added;
• and
• a digital signal adder receiving and combining the intermediate digitized signals produced by the plurality of ADCs to produce a digitized signal.

A signal-linearization system for reducing nonlinear distortions in an output signal generated by a signal converter device when converting an input signal between analog and digital forms, the system comprising:

• a signal adder adding a dither waveform to the input signal;
• a signal converter device converting the input signal with the added dither waveform from one of the analog and digital forms into an output signal having the other of the analog and digital forms, the dither waveform being adapted to suppress nonlinear distortions by being substantially uncorrelated with the input signal and by having a signal level that is approximately equal to or greater than a maximum signal level of the input signal, a frequency spectrum that is substantially uniformly distributed within a predetermined frequency range, a peak-to-average ratio that is approximately equal to the square root of two, and a distribution of quantization levels that is substantially balanced;
• and
• a dither waveform removal module removing the dither waveform from the output signal.

A signal-linearization system for reducing nonlinear distortions in an analog output signal by a digital-to-analog converter (DAC) when converting a digital input signal from digital to analog form, the system comprising:

• a waveform generator producing a digital dither waveform, the digital dither waveform being substantially uncorrelated with the digital input signal and having a signal level that is approximately equal to or greater than a maximum signal level of the digital input signal;
• a digital signal adder adding the digital dither waveform to the digital input signal;
• a DAC converting the digital input signal with the added digital dither waveform into an analog output signal, the digital dither waveform operating to suppress nonlinear distortions attributed to circuitry of the DAC;
• and
• a dither waveform removal module in communication with the DAC to receive the analog output signal, the dither waveform removal module removing from the analog output signal an analog counterpart of the digital dither waveform and producing a linearized analog output signal.