Techniques are disclosed for managing the timing between two asynchronous clocks. The techniques are particularly well-suited for synchronizing the reference clock with the divided clock in a phase coherent DSM PLL application, but can be more broadly applied to any application that includes a need for synchronizing a data bus across a clock boundary. In one example embodiment, the techniques are implemented in a retime word circuit operatively coupled between a DSM and the divide-by-N integer divider of a PLL application. The retime word circuit receives the divide word from the DSM and generates a retimed divide word that can be applied to the divider. The retime word circuit maintains the reference clock frequency throughput, and forces the divide word seen by the divider to change only at end of a given divide cycle.

A second-order ΔΣ modulator includes: a two-stage integrator; a first arithmetic operation circuit; and a second arithmetic operation circuit. The two-stage integrator includes a plurality of adder arrays, each of which includes a plurality of adders. The plurality of adder arrays includes first to fourth adder arrays. An output of a last stage of the second adder array is fed back as an input of a first stage of the first adder array. An output of a last stage of the fourth adder array is fed back as an input of a first stage of the third adder array. A sum bit string obtained in the first adder array is input to the third adder array. A sum bit string obtained in the second adder array is input to the fourth adder array.

A second-order modulator includes: a two-stage integrator; a first arithmetic operation circuit; and a second arithmetic operation circuit. The two-stage integrator includes a plurality of adder arrays, each of which includes a plurality of adders. The plurality of adder arrays includes first to fourth adder arrays. An output of a last stage of the second adder array is fed back as an input of a first stage of the first adder array. An output of a last stage of the fourth adder array is fed back as an input of a first stage of the third adder array. A sum bit string obtained in the first adder array is input to the third adder array. A sum bit string obtained in the second adder array is input to the fourth adder array.

A digital microphone includes built-in self-test features. The features may include capability to apply different bias voltages to a MEMS capacitor sensor of the digital microphone, simulating application of different sound pressures to the digital microphone. The features may also include a digital oscillator, for applying a test signal to an analog front end of the microphone.

A digital microphone includes built-in self-test features. The features may include capability to apply different bias voltages to a MEMS capacitor sensor of the digital microphone, simulating application of different sound pressures to the digital microphone. The features may also include a digital oscillator, for applying a test signal to an analog front end of the microphone.

Provided, among other things, is an apparatus that converts a signal from one sampling domain to another, and which includes: an input line for accepting an input signal and a processing branch. The processing branch includes a branch input coupled to the input line for inputting data samples that are discrete in time and in value, a quadrature downconverter, a first and second lowpass filter, a first and second polynomial interpolator, and a rotation matrix multiplier that provides a phase rotation. The processing branch generates data samples at a sampling interval that differs from the sampling interval associated with the signal provided to the branch input, e.g., with the difference in the sampling intervals depending on fluctuations in the output period of a local oscillator. Certain embodiments include multiple such processing branches, e.g., operating on different frequency bands of the input signal.

Certain aspects of the present disclosure provide apparatus and techniques for segmenting a digital input signal for digital-to-analog conversion. For example, certain aspects provide a segmentation circuit for generating digital signal segments for a digital-to-analog converter. The segmentation circuit generally includes a modulo function logic circuit configured to generate a modulo output signal based on a digital input signal and a divisor input signal and a modulo range extension logic circuit configured to selectively direct the modulo output signal or the divisor input signal to an output of the segmentation circuit. In certain aspects, the output of the segmentation circuit may be used by the digital-to-analog converter to generate an analog signal based on the digital input signal.

A digital-to-analog converter performs a computation process to start the computation based upon the second clock signal with respect to the digital data of music sound if the computation is not under execution when the control signal is outputted by the signal output process, a control process to inhibit the computation based upon the second clock signal from being started with respect to the digital data of music sound until the computation is not under execution when the computation is under execution, and an output process to convert a computation result of the computation process into an analog signal and output the analog signal.

A digital-to-analog converter performs a computation process to start the computation based upon the second clock signal with respect to the digital data of music sound if the computation is not under execution when the control signal is outputted by the signal output process, a control process to inhibit the computation based upon the second clock signal from being started with respect to the digital data of music sound until the computation is not under execution when the computation is under execution, and an output process to convert a computation result of the computation process into an analog signal and output the analog signal.

Provided are, among other things, systems, apparatuses, methods and techniques for converting a discrete-time quantized signal into a continuous-time, continuously variable signal. An exemplary converter preferably includes: (1) multiple oversampling converters, each processing a different frequency band, operated in parallel; (2) multirate (i.e., polyphase) delta-sigma modulators (preferably second-order or higher); (3) multi-bit quantizers; (4) multi-bit-to-variable-level signal converters, such as resistor ladder networks or current source networks; (5) adaptive nonlinear, bit-mapping to compensate for mismatches in the multi-bit-to-variable-level signal converters (e.g., by mimicking such mismatches and then shifting the resulting noise to a frequently range where it will be filtered out by a corresponding bandpass (reconstruction) filter); (6) multi-band (e.g., programmable noise-transfer-function response) bandpass delta-sigma modulators; and/or (7) a digital pre-distortion linearizer (DPL) for canceling noise and distortion introduced by an analog signal bandpass (reconstruction) filter bank.