A technique for generating analog waveforms includes combining a desired, in-band signal with a randomizing, out-of-band signal at an input of a DAC, operating the DAC to generate DAC output based on a combination of the desired signal and the randomizing signal, and filtering the DAC output to pass the desired signal while removing the randomizing signal.

A segmented digital-to-analog converter (DAC) includes DAC segments, an overrange DAC, and a dither control circuit. Each DAC segment includes a plurality of DAC cells for generating an analog output signal based on input data to each DAC segment. The overrange DAC generates an analog output signal based on a control signal. The dither control circuit adds a dither to first input data supplied to a higher-order DAC segment, subtract a portion of the dither from second input data supplied to a lower-order DAC segment, and generate the control signal for subtracting a remaining portion of the dither from an output of the segmented DAC in an analog domain. The dither added to the first input data may be one of +1, 0, and −1 and the portion of the dither subtracted from the second input data may be a half of the dither added to the first input data.

Herein disclosed is an example analog-to-digital converter (ADC) and methods that may be performed by the ADC. The ADC may derive a first code that approximates a combination of an analog input value of the ADC and a dither value for the ADC sampled on a capacitor array. The ADC may further derive a second code to represent a residue of the combination with respect to the first code applied to the capacitor array. The ADC may combine the numerical value of the first code and the numerical value of the second code to produce a combined code applied to the capacitor array for deriving a digital output code. Combining the numerical value of the first code and the numerical value of the second code in the digital domain can provide for greater analog-to-digital (A/D) conversion linearity.

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.

Apparatuses and methods for reducing vertical fixed pattern noise in imaging systems are disclosed herein. An example apparatus may include an analog dithering circuit coupled to randomly add an offset voltage to a first reference voltage in response to a random binary signal during an analog to digital conversion operation, and a ramp generator circuit coupled to receive the first reference voltage, and provide a second reference voltage in response, wherein the randomly added offset voltage to the first reference is also present in the second reference voltage.

Disclosed is a successive approximation register (SAR) analog to digital converter (ADC) that uses two or more comparators. This allows the output of one comparator to be latched while the other comparators are comparing and switching. Statistical measures are used to correct the offsets of one or more of the comparators. If a statistically significant mismatch in the number of 1's and 0's occurs in a subset of the bits, adjustments to the offsets of one or more of the comparators are made until there is roughly an equal number of 1 and 0 values. This can reduce or eliminate the need for dedicated offset correction cycles.

A circuit configured to sense an input analog signal generated by a sensor at a first frequency and to generate an output digital signal indicative of the sensed input analog signal. The circuit includes a conditioning circuit, an ADC, a feedback circuit, and a low-pass filter. The conditioning circuit is configured to receive the input analog signal and to generate a conditioned analog signal. The ADC is configured to provide a converted digital signal based on the conditioned analog signal. The feedback circuit includes a band-pass filter configured to selectively detect a periodic signal at a second frequency higher than the first frequency and to act on the conditioning circuit to counter variations of the periodic signal at the second frequency. The low-pass filter is configured to filter out the periodic signal from the converted digital signal to generate the output digital signal.

A segmented digital-to-analog converter (DAC) includes DAC segments, an overrange DAC, and a dither control circuit. Each DAC segment includes a plurality of DAC cells for generating an analog output signal based on input data to each DAC segment. The overrange DAC generates an analog output signal based on a control signal. The dither control circuit adds a dither to first input data supplied to a higher-order DAC segment, subtract a portion of the dither from second input data supplied to a lower-order DAC segment, and generate the control signal for subtracting a remaining portion of the dither from an output of the segmented DAC in an analog domain. The dither added to the first input data may be one of +1, 0, and −1 and the portion of the dither subtracted from the second input data may be a half of the dither added to the first input data.

Disclosed is a successive approximation register (SAR) analog to digital converter (ADC) that uses two or more comparators. This allows the output of one comparator to be latched while the other comparators are comparing and switching. Statistical measures are used to correct the offsets of one or more of the comparators. If a statistically significant mismatch in the number of 1's and 0's occurs in a subset of the bits, adjustments to the offsets of one or more of the comparators are made until there is roughly an equal number of 1 and 0 values. This can reduce or eliminate the need for dedicated offset correction cycles.

A circuit configured to sense an input analog signal generated by a sensor at a first frequency and to generate an output digital signal indicative of the sensed input analog signal. The circuit includes a conditioning circuit, an ADC, a feedback circuit, and a low-pass filter. The conditioning circuit is configured to receive the input analog signal and to generate a conditioned analog signal. The ADC is configured to provide a converted digital signal based on the conditioned analog signal. The feedback circuit includes a band-pass filter configured to selectively detect a periodic signal at a second frequency higher than the first frequency and to act on the conditioning circuit to counter variations of the periodic signal at the second frequency. The low-pass filter is configured to filter out the periodic signal from the converted digital signal to generate the output digital signal.