A microphone assembly includes a transducer element and a processing circuit. The processing circuit includes an analog-to-digital converter (ADC) configured to receive, sample and quantize a microphone signal generated by the transducer element to generate a corresponding digital microphone signal. The processing circuit includes a feedback path including a digital loop filter configured to receive and filter the digital microphone signal to provide a first digital feedback signal and a digital-to-analog converter (DAC) configured to convert the first digital feedback signal into a corresponding analog feedback signal. The processing circuit additionally includes a summing node at the transducer output configured to combine the microphone signal and the analog feedback signal.

A Sigma-Delta analog to digital converter (ADC) is described. The Sigma-Delta ADC includes a series arrangement of a gain tracker, a first discrete-time integrator stage and a quantizer between an ADC input and an ADC output. The Sigma-Delta ADC includes a digital to analog converter (DAC) having a DAC input and a DAC output connected to the gain tracker. The Sigma-Delta analog to digital converter includes a controller having a control input connected to the quantizer output. The controller provides a digital input to the DAC input and provides a gain control signal to the gain tracker.

A system, comprising: a sigma-delta modulator using an integrator of a cascade-of-integrator feedback topology to perform operations is disclosed. The operations can comprise in response to receiving a gain value, applying the gain value to a group of feed-forward coefficients, determining a change in the gain value, and adjusting, during a clock cycle of a defined time period, a plurality of state variables of the sigma-delta modulator by multiplying each of the state variables by the scale factor that is a ratio of the gain value after determining the change in the gain value the gain value before determining the change in the gain value.

A resonator-based sensor and a sensing method thereof for sensing a change in a material that is subject to be sensed which include: generating an oscillation voltage signal by amplifying a current signal output from a resonator in accordance with a physical-chemical change of the material; and generating a gain control signal corresponding to a motional resistance and a clock signal corresponding to a resonant frequency of the resonator are provided.

A digital microphone compresses a large voltage swing signal from a MEMS capacitor to a signal suitable for processing by integrated circuitry. The compression may be performed in an analog domain by selectively coupling adjustment capacitors in parallel to the MEMS capacitor. The digital microphone may decompress the signal in the digital domain using a decompression technique substantially an inverse of the compression performed in the analog domain.

A signal processing arrangement has a signal input for connecting a capacitive sensor. An amplifier circuit is coupled between the signal input and a feedback point. A loop filter is coupled downstream to the feedback point. A quantizer is connected downstream to the loop filter and provides a multi-bit output word. The multi-bit output word consists of one or more higher significance bits and one or more lower significance bits. A first feedback path is coupled between a quantizer and the feedback point for providing a first feedback signal to the feedback point being representative of the one or more lower significance bits. A second feedback path is coupled to the quantizer for providing a second feedback signal to the signal input being representative of the one or more higher significance bits.

A microphone assembly includes a transducer and a processing circuit. The processing circuit includes an analog-to-digital converter (ADC) configured to receive, sample and quantize an electrical signal generated by the transducer to generate a corresponding digital signal. The processing circuit includes a feedback path including a digital loop filter configured to receive and filter the digital signal to provide a first digital feedback signal and a digital-to-analog converter (DAC) configured to convert the first digital feedback signal into a corresponding analog feedback signal. The processing circuit additionally includes a summing node configured to combine the electrical signal and the analog feedback signal.

A sigma-delta ADC is described including a passive filter with an input coupled to the ADC input and a filter output. A gain stage has an input connected to the filter output. A quantiser has an input connected to the gain stage output and a quantiser output. The passive filter includes a first filter resistor between the filter input and the filter output and a filter capacitor having first terminal coupled to the filter output. A feedback resistor is coupled between the quantiser output and the filter output and receives a negative of the value of the output to provide negative feedback to the filter output. The gain stage has a capacitor and resistor in series, and a gain element connected to the gain stage input and an output connected to the gain stage output. One terminal of the gain stage capacitor is connected to the gain element output.

A resonator-based sensor and a sensing method thereof for sensing a change in a material that is subject to be sensed which include: generating an oscillation voltage signal by amplifying a current signal output from a resonator in accordance with a physical-chemical change of the material; and generating a gain control signal corresponding to a motional resistance and a clock signal corresponding to a resonant frequency of the resonator are provided.

A nested ?-? analog-to-digital conversion system and method, compromising: an analog filter, an analog comparator, a first feedback digital-to-analog converter (DAC), a second feedback DAC placed in front of the first feedback DAC, and a digital filter and an MSB quantizer placed at the output of the analog comparator; wherein the input of the first feedback DAC is connected to the output of the analog comparator; the analog filter, the analog comparator, and the first feedback DAC form an internal analog ?-? loop; the input of the second feedback DAC is connected to the output of the MSB quantizer; the output of the second feedback DAC is connected to the output of the first feedback DAC and to the input of the analog filter; and the second feedback DAC, the internal analog ?-? loop, the digital filter, and the MSB quantizer form an external hybrid ?-? loop.