According to one embodiment of the present invention, provided is an analog to digital converter. The analog-to-digital converter according to one embodiment of the present invention comprises an analog amplification unit and a flash conversion unit, wherein the analog amplification unit may have a structure in which in which two input terminal circuits that alternately operate share a single amplifier. Accordingly, the analog-to-digital converter according to one embodiment of the present invention can be implemented in a smaller area and operate at low power, and can have a high resolution while operating at a high speed.

This application relates an activity detector (100) for detecting signal activity in an input audio signal (S.sub.IN), such as may be used for always-on speech detection. The activity detector has a first time-encoding modulator (TEM) 101 including a first hysteretic comparator (201) for generating a PWM (pulse-width modulation) signal based on the input audio signal. A second TEM (103) having a second hysteretic comparator (401) is arranged to receive a reference voltage (V.sub.MID) and generate a clock signal (S.sub.CLK). A time-decoding converter (102) receives the clock signal and generates count values of a number of cycles of the clock signal in periods defined by the PWM signal. An activity monitor (104) is responsive to a count signal (S.sub.CT) from the TDC 102 to determine whether the input audio signal comprises signal activity above a defined threshold.

A receiver includes a variable resolution analog-to-digital converter (ADC) and variable resolution processing logic/circuitry. The processing logic may use feed-forward equalization (FFE) techniques to process the outputs from the ADC. When receiving data from a channel having low attenuation, distortion, and/or noise, the ADC and processing logic may be configured to sample and process the received signal using fewer bits, and therefore less logic, than when configured to receiving data from a channel having a higher attenuation, distortion, and/or noise. Thus, the number of (valid) bits output by the ADC, and subsequently processed (e.g., for FFE equalization) can be reduced when a receiver of this type is coupled to a low loss channel. These reductions can reduce power consumption when compared to operating the receiver using the full (i.e., maximum) number of bits the ADC and processing logic is capable of processing.

An analog-to-digital converter and a clock generation circuit thereof are provided. The clock generation circuit comprises cascaded clock generation modules. The clock generation module at each stage is configured to generate a corresponding internal clock signal, and each stage of the clock generation module comprises a delay module and a logic gate module. The second input end of the N-th stage of the logic gate module is connected to the output end of the previous stage of the logic gate module, and the output end of the logic gate module is configured to output an internal clock, so that each stage of the clock generation module can generate one internal clock signal.

A current source and/or current sink digital-to-analog converter (DAC) includes a DAC circuit that converts a digital code to an analog current or voltage signal, an optional transconductance circuit that converts a voltage output of the DAC circuit into a current signal, and an output circuit that amplifies a current output of the DAC circuit or optionally amplifies a current output of the transconductance circuit to set a desired high current output for application to an output of the current source and/or current sink DAC. A power supply control current may be coupled to a power supply circuit that supplies power to the output circuit of the current source and/or current sink DAC. The power supply control current adjusts the output of the power supply circuit to cause the current source and/or current sink DAC to operate at a higher power efficiency.

An exemplary incremental two-step capacitance-to-digital converter (CDC) with a time-domain sigma-delta modulator (TDΔΣM) includes a voltage-controlled oscillator (VCO)-based integrator that can be used in a low-order loop configuration. Example prototypes are disclosed, which when fabricated in 40-nm CMOS technology, provides CDC resolution of 0.29 fF while dissipating only 0.083 nJ per conversion.

In a system for converting digital data into a modulated optical signal, an electrically controllable device, including a modulator having one or more actuating electrodes, provides an analog-modulated optical signal that is modulated in response to output data bits of a digital-to-digital mapping. A digital-to-digital conversion provides the mapping of input data words to the output data bits. The mapping enables adjustments to correct for non-linearities and other undesirable characteristics, thereby improving signal quality.

An analog-to-digital circuit that digitizes an analog voltage. The analog-to-digital circuit includes plural comparators functionally connected to form a tree that has levels i, and each level i has branches j, and an encoder connected to the plural comparators and configured to generate a digitized value of an input analog voltage. Each comparator from a level i has first and second outputs, and each of the first and second outputs is electrically connected to an input of different comparators from a next level i+1 of the tree.

Methods and apparatus for adaptively generating a reference voltage (V.sub.REF) for biasing a switch driver and corresponding switch in a digital-to-analog converter (DAC). The adaptive biasing scheme may be capable of tracking process, voltage, and temperature (PVT) of the DAC. An example DAC generally includes a plurality of DAC cells, each DAC cell comprising a current source, a switch coupled in series with the current source, and a switch driver coupled to a control input of the switch, the switch driver being configured to receive power from a first power supply rail referenced to a reference potential node; a regulation circuit comprising a first transistor coupled between the reference potential node for the DAC and the switch driver in at least one of the plurality of DAC cells; and a V.sub.REF generation circuit coupled to the regulation circuit and configured to adaptively generate a V.sub.REF for the regulation circuit.

A system and method for equalization of a linear or non-linear system. The system includes an adder configured to add an analog reference signal and an input signal, a processing system configured to process a sum of the analog reference signal and the input signal, a non-linear equalizer (NLEQ) configured to process an output of the processing system to remove a distortion incurred by the processing system, a calibration circuitry configured to generate a reconstructed reference signal in digital domain based on measurement of the analog reference signal, and generate coefficients for the NLEQ based on the reconstructed reference signal and the output of the processing system, and a subtractor configured to subtract the reconstructed reference signal from an output of the NLEQ. The analog reference signal may be a sinusoid including single or multiple tones of sinusoids. The non-linear system may be an analog-to-digital converter (ADC).