In accordance with embodiments of the present disclosure, a processing system may include multiple selectable processing paths for processing an analog signal in order to reduce noise and increase dynamic range. Techniques are employed to transition between processing paths and calibrate operational parameters of the two paths in order to reduce or eliminate artifacts caused by switching between processing paths.

The present disclosure relates to a method and system for tone signal removal from a noisy signal that includes a desired signal in combination with the tone signal. The method and system provides an artificial or estimated undesired tone signal with the same frequency as the undesired tone signal, which, in combination with an estimated phasor, is available to filter or subtract a noisy component from the noisy signal and to provide the filtered or clean desired signal.

Transition smoothing apparatus for reducing spurious input to a system under feedback control connected to a control loop. The apparatus includes a loop filter to integrate an error between an input signal applied to the loop filter and an output signal of the system under feedback control, an analog-to-digital converter to provide digitized integrated error values, a controller to generate output values supplied to the system under feedback control in response to the digitized integrated error values and in a start-up sequence to control a feedback digital-to-analog converter according to the digitized integrated error values to supply a first control signal to the loop filter and control the system under feedback control to generate a second control signal, and an alignment detector to detect phase alignment between the first control signal and the second control signal to control a smooth transition into closed loop operation of the control loop.

The present disclosure relates to a method and system for tone signal removal from a noisy signal that includes a desired signal in combination with the tone signal. The method and system provides an artificial or estimated undesired tone signal with the same frequency as the undesired tone signal, which, in combination with an estimated phasor, is available to filter or subtract a noisy component from the noisy signal and to provide the filtered or clean desired signal.

A system and method of generating a synthetic time period output signal for a fork density sensor (601) which produces a consistent and low-noise output signal (705) which is identical in frequency to the frequency at which the fork density meter vibrates. Such a synthetic Analog signal generated by a meter signal prevents any real noise from the pickoffs from propagating to the output meter and removes process noise and interference from the produced output signal.

In accordance with embodiments of the present disclosure, a processing system may include multiple selectable processing paths for processing an analog signal in order to reduce noise, increase dynamic range, and mask audio artifacts associated with a change in noise floor. Techniques are employed to transition between processing paths and calibrate operational parameters of the two paths in order to reduce or eliminate artifacts caused by switching between processing paths.

The present disclosure provides systems and methods for identifying and reporting failures of an analog to digital (A/D) conversion system. The systems and methods are configured to detect and report a failure of a preamplifier of the A/D conversion system and/or a failure of a A/D converter of the A/D conversion system. A high frequency component can be included in the input of an A/D converter. The A/D converter is configured to output a digital value to the A/D conversion system, wherein the digital value includes the high frequency component of the A/D converter input. The A/D conversion system is configured to determine an output status, including a frequency component and a corresponding amplitude, and to determine a failure of the A/D conversion system based on the determined output status. The A/D conversion system can report a change in, or a failure of, the A/D converter, and can operate or prevent operation of protection elements.

Transition smoothing apparatus for reducing spurious input to a system under feedback control connected to a control loop. The apparatus includes a loop filter to integrate an error between an input signal applied to the loop filter and an output signal of the system under feedback control, an analog-to-digital converter to provide digitized integrated error values, a controller to generate output values supplied to the system under feedback control in response to the digitized integrated error values and in a start-up sequence to control a feedback digital-to-analog converter according to the digitized integrated error values to supply a first control signal to the loop filter and control the system under feedback control to generate a second control signal, and an alignment detector to detect phase alignment between the first control signal and the second control signal to control a smooth transition into closed loop operation of the control loop.

DAC design uses a passive reconstruction filter. The reconstruction filter includes a notch filter and series peaking filter. The notch filter provides notch filtering at the DAC clock frequency. The peaking filter increases signal bandwidth while attenuating frequency content at harmonics of the DAC clock frequency. The notch filter can be an LC notch filter with a notch inductor Ln and a notch capacitor Cn. The peaking filter can be a series peaking inductor Ls (shunted with a filter capacitor Cp). In a differential configuration, the passive reconstruction filter can be LC notch filters (with Ln notch inductors), and the peaking filter can be Ls peaking inductors coupled in series to the LC notch filters. The Ln notch inductors, Ls peaking inductors can be mutually wound as single inductors. For an example direct conversion RF transmit chain, IQ signal paths are implemented with differential DAC designs including passive reconstruction filters.

Systems and methods for identifying and reporting failures of an analog to digital (A/D) conversion system are presented. The systems and methods may detect and report a problem of input circuitry of an A/D converter and/or an A/D converter itself. For example, an identifiable characteristic can be introduced into the input signal provided to an A/D converter. The A/D converter may output a digital value that includes the identifiable characteristic of the A/D converter input. A monitoring system may determine and/or report a change in, or a failure of, the A/D converter or input circuitry thereto, based on the identification, non-existence of, or variation in the identifiable characteristic in the digital output.