A method of applying digital pre-distortion includes: outputting, by a look-up table, a first table value based on an input digital signal; adding the first table value and the input digital signal to generate a first combined signal comprising a first combined value having a first integer coefficient and a first fractional coefficient; separating the first integer coefficient from the first fractional coefficient to generate a first integer signal representing the first integer coefficient and a first fractional signal representing the first fractional coefficient; generating a delta-sigma modulated signal based on the first fractional signal; converting, by a first digital-to-analog, a first digital signal into a first analog signal, wherein the first digital signal is representative of the first integer signal; and converting, by a second DAC, a second digital signal into a second analog signal, wherein the second digital signal is representative of the delta-sigma modulated signal.

A baseband processing unit includes a baseband processor configured to receive a plurality of component carriers of a radio access technology wireless service, and a delta-sigma digitization interface configured to digitize at least one carrier signal of the plurality of component carriers into a digitized bit stream, for transport over a transport medium, by (i) oversampling the at least one carrier signal, (ii) quantizing the oversampled carrier signal into the digitized bit stream using two or fewer quantization bits.

Systems, devices, and methods related to low-noise, high-accuracy single-ended continuous-time sigma-delta (CTSD) analog-to-digital converter (ADC) are provided. An example single-ended CTSD ADC includes a pair of input nodes to receive a single-ended input signal and input circuitry. The input circuitry includes a pair of switches, each coupled to one of the pair of input nodes; and an amplifier to provide a common mode signal at a pair of first nodes, each before one of the pair of switches. The single-ended CTSD ADC further includes digital-to-analog converter (DAC) circuitry; and integrator circuitry coupled to the input circuitry and the DAC circuitry via a pair of second nodes.

A digital conversion system including a sigma-delta converter, a tone generator that generates injects a tone signal into the conversion path of the sigma-delta converter at a frequency that is outside operating signal frequency range, a tone detector that isolates and detects a level of the injected tone signal and provides a corresponding tone level value, a tone ratio comparator that converts the tone level value into a tone level ratio and that compares the converted tone level ratio with an expected tone level ratio to provide an error signal, and a loop controller that converts the error signal to a correction signal to adjust a loop filter frequency the sigma-delta converter. Tones may be serially injected one at a time or simultaneously in parallel for determining a measured tone level ratio for comparison with a corresponding one of multiple stored expected tone level ratios.

During a sampling phase, an analog front end circuit connects input of a first sampling capacitor to an analog input signal and input of a second sampling capacitor to a reference signal, and connects first and second hold capacitors to ground. During a partial tracking phase, input of the first sampling capacitor is connected to the reference voltage and the input of the second sampling capacitor is connected to the analog input signal. The first hold capacitor is connected to a first output of a gain amplifier and the second hold capacitor to a second output of the gain amplifier. Output of the first sampling capacitor is coupled to a first input of an amplifier and output of the second sampling capacitor is coupled to a second input of the amplifier.

A differential delta-sigma-modulator has an integrator including a pair of single-ended amplifiers. A sample clock is driving a first switchable capacitor configuration and a second switchable capacitor configuration at a predetermined switching cycle. The first switchable capacitor configuration is adapted for sampling respective outputs from the pair of single-ended amplifiers on a pair of output sampling capacitors in the first part of the switching cycle. The second switchable capacitor configuration is adapted for charging a common mode capacitor with the average voltage of the voltage sampled by the pair of output sampling capacitors in the second part of the switching cycle. The voltage across the common mode capacitor represents the common mode voltage for the integrator.

A delta-sigma modulator includes a quantizer, a signal propagation path including a plurality of cascaded integrators coupled between the input node and the quantizer, and a feedback network including a plurality of digital-to-analog converters. In a calibration mode of operation, a first digital-to-analog converter of the plurality of digital-to-analog converters of the feedback network receives a signal including a periodic alternated digital sequence, the first digital-to-analog converter being coupled to a first integrator of the plurality of cascaded integrators, integrators of the plurality of cascaded integrators other than the first integrator operate in a gain mode of operation, the delta-sigma modulator generates a digital test signal at an output of the quantizer based on the signal including the periodic alternated digital sequence, and calibration circuitry generates a calibration signal based on the digital test signal and a reference digital word.

An integrator and an analog-to-digital converter are provided. The analog-to-digital converter includes the integrator, a comparison circuit and a control logic circuit. The integrator includes an operational amplifier, offset capacitors, input capacitors, integral capacitors and controllable switches. The input capacitors and the integral capacitors are connected to the operational amplifier via controllable switches, so that the integrator operates in various operation modes. Operation states of the offset capacitors in a first phase and a second phase of an operation cycle are controlled by switching on or off the controllable switches. Therefore, an offset voltage of the integrator is eliminated, and conversion efficiency and conversion accuracy of the analog-to-digital converter is improved.

An integrated circuit includes a continuous time delta sigma analog-to-digital converter (CTDS ADC) and a test circuit for testing the CTDS ADC. The test circuit converts multi-bit digital reference data to a single-bit digital stream. The test circuit then passes the single-bit digital stream to a finite impulse response digital-to-analog converter (FIR DAC). The FIR DAC converts the single-bit digital stream to an analog test signal. The analog test signal is then passed to the CTDS ADC. The CTDS ADC converts the analog test signal to digital test data. The test circuit analyzes the digital test data to determine the accuracy of the CTDS ADC.

Provided is a system that includes: a plurality of touch sensors sharing a signal medium, each touch sensor in the plurality being configured to output set of frequencies on the signal medium responsive to being touched, each touch sensor in the plurality being configured to output a different set of frequencies; an analog to digital converter electrically coupled to the signal medium and configured to receive the sets of frequencies from the touch sensors and convert the sets of frequencies to digital representations of the sets of frequencies in the time domain; a processor communicatively coupled to the analog to digital converter and configured to execute a fast Fourier transform of the digital representations from the time domain into digital representations in the frequency domain; and an address decoder operative to transform the digital representations in the frequency domain into identifiers of touch sensors among the plurality of touch sensors.