A multilevel analog to digital converter (ADC) is composed of noise shaping filter and multi-level quantizer, where said quantizer is made from an array of comparators, each coupled with one reference level, the said quantizer is coupled with a thermometric digital to analog converters (DAC) in the feedback path, the said DAC output is compared with ADC input and error is fed to noise shaping filter, said reference levels of each quantizer is generated from a digital to analog converter coupled with a digital quantizer reference controller and said digital quantizer reference controller is randomly changing the reference levels in a way that quantizer coupled DAC elements are indirectly randomised to improve the overall linearity and noise performance of the converter.

Σ-Δ modulator and method for reducing nonlinear error and gain error. The Σ-Δ modulator includes: a plurality of sampling capacitors, configured to sample an input voltage or simultaneously sample an input voltage and a reference voltage signal; an operational amplifier; a plurality of switches, configured to select to sample the input voltage and the reference voltage signal; an integrating capacitor, configured to perform integration superposition on the input voltage and the reference voltage signal sampled by the sampling capacitors; and a control assembly, configured to control, to select to sample the reference voltage signal or simultaneously sample the input voltage and the reference voltage signal within a cycle, and to perform clock control on the sampling capacitors that simultaneously sample the input voltage and the reference voltage signal within a next cycle. During input sampling, Vref signals of two capacitors are simultaneously sampled to offset an overlarge area of the integrating capacitor, and a pseudo random number is used to control a polling timing of the capacitors to solve a problem of idle tone of a Σ-Δ modulator, so that the area of the integrating capacitor is effectively reduced, thereby reducing manufacturing costs of an integrated circuit and reducing an output swing.

Various embodiments of the present technology may comprise methods and apparatus for an amplifier circuit. Methods and apparatus for an amplifier circuit according to various aspects of the present invention may be utilized in a digital-to-analog converter. The amplifier circuit may comprise a first operational amplifier with a feedback circuit. The feedback circuit may comprise an inverting amplifier circuit.

Described is an apparatus comprising a first circuitry, a second circuitry, a first capacitor array, and a second capacitor array. The first circuitry may have an oscillator. The first capacitor array may have a set of first capacitors to tune the oscillator. The second capacitor array may have a second capacitor to tune the oscillator. A capacitance of the second capacitor may be greater than an average capacitance of the first capacitors. The second circuitry may be operable to synchronously activate the second capacitor and deactivate a number N of the first capacitors, and to synchronously deactivate the second capacitor and activate the N first capacitors, based on a predetermined sequence.

A digital-to-analog converter is provided. The digital-to-analog converter comprises an input configured to receiving a first digital control code for controlling a plurality of digital-to-analog converter cells. Further, the digital-to-analog converter comprises a code converter circuit configured to converter the first digital control code to a second digital control code. Further, the digital-to-analog converter comprises a shift code generation circuit configured to generate a shift code based on a code difference between the first digital control code and a third digital control code. The digital-to-analog converter additionally comprises a bit-shifter circuit configured to bit-shift the second digital control code based on the shift code in order to obtain a modified second digital control code. The digital-to-analog converter comprises a cell activation circuit configured to selectively activate one or more of the plurality of digital-to-analog converter cells based on the modified second digital control code. Each activated digital-to-analog converter cell is configured to output a respective cell output signal. Further, the digital-to-analog converter comprises an output configured to output an analog output signal based on the cell output signals.

What is provided is a subtractor, as a re-quantization device, which is configured to detect re-quantization noise, a discrete time filter which is configured to perform frequency weighting on the detected re-quantization noise, an adder which is configured to add an additional signal to quantization noise, and an additional signal selector which is configured to select a value at the present time of a column of an additional signal for minimizing the magnitude of quantization noise having been subjected to frequency weighting evaluated one sampling or more later.

A pulse density modulation method includes the following steps: S01, obtaining a number of bits n of a binary density value d, setting a number of bits of a counter as n, an initial value of the counter is 0 or 1; S02, searching for a rightmost 1: obtaining a number of bits j of the rightmost 1 of a current value i of the counter counted from right to left; a number in the counter is a binary number; a minimum value of j is 1; S03, determining whether corresponding bits are equal; S04, adding the value i of the counter by 1, proceeding to a next period, and turning to the step S02.

A system may include a digital delta-sigma modulator configured to receive a digital audio input signal and quantize the digital audio input signal into a quantized signal, a filter configured to receive the quantized signal and perform filtering on the quantized signal to generate a filtered quantized signal, the filter having a variable group delay, and a current-mode digital-to-analog converter configured to receive the filtered quantized signal and convert the filtered quantized signal into an equivalent current-mode analog audio signal.

An apparatus for dynamic range enhancement (DRE) which receives an input signal and provides a DRE output signal is presented. The apparatus has an error correction circuit to apply an error correction factor to the input signal such that the DRE output signal provided by the apparatus is dependent on the input signal and the error correction factor. The error correction factor is representative of an error generated by the apparatus.

A continuous time Delta-Sigma (CT-) modulator has an input node configured to receive an input signal and an output node configured to output a digital output signal. The CT- modulator includes a feedback loop with a summation circuit configured to sum the digital output signal with a jitter perturbed test signal to generate a signal supplied to an input of a digital to analog converter circuit. A single tone signal is injected with a jitter error of a clock signal to generate the jitter perturbed test signal. A processing circuit processes the digital output signal to detect a signal to noise ratio of the CT- modulator. The detected signal to noise ratio is indicative of presence of jitter in the clock signal.