A calibration circuit configured to calibrate a signal of a sensing unit comprises: an amplifier, a first impedance element and a second impedance element. The amplifier has a first input terminal, a second input terminal and an output terminal. The first input terminal is coupled to a first terminal of the sensing unit, the second input terminal is coupled to a reference voltage, and the output terminal is feedback to the first input terminal and outputs the readout signal. A first terminal of the first impedance element is coupled to the first input terminal of the amplifier, and a second terminal of the first impedance element is coupled to a calibration voltage. A first terminal of the second impedance element is coupled to the first terminal of the first impedance element, and a second terminal of the second impedance element is coupled to the output terminal of the amplifier.

This document describes apparatuses and techniques for termination for single-ended (SE) mode operation of a memory device. In various aspects, a termination circuit can terminate an unused signal line of a differential pair to a ground or power rail using a switch element when operating in the SE mode. The termination circuit may also disconnect the unused signal line from a first input of a differential amplifier and connect a reference voltage to the first input of the differential amplifier. Based on the reference voltage, the differential amplifier amplifies an SE signal received using another signal line of the differential pair at a second input of the differential amplifier to provide a clock signal for memory operations. Thus, the termination circuit may reduce an amount by which noise associated with the unused signal line affects the differential amplifier when the memory device operates in SE mode.

The disclosure provides a time gain compensation (TGC) circuit. The TGC circuit includes an impedance network. A differential amplifier is coupled to the impedance network. The differential amplifier includes a first input port, a second input port, a first output port and a second output port. A first feedback resistor is coupled between the first input port and the first output port. A second feedback resistor is coupled between the second input port and the second output port. The impedance network provides a fixed impedance to the differential amplifier when a gain of the TGC circuit is changed from a maximum value to a minimum value.

A power amplifier provides reduction of click and pop in audio applications. The power amplifier includes a first amplifier and an auxiliary amplifier. The auxiliary amplifier is used to ramp the power amplifier output from ground to an offset voltage to reduce the “click and pop” sound. The first amplifier and the auxiliary amplifier having a shared feedback loop. An output of the first amplifier and an output of the auxiliary amplifier may be switchably coupled to the shared feedback loop. A wave generator controls a switch to couple the first amplifier output or the auxiliary amplifier output to the shared feedback loop.

Example circuitry includes a first circuit to provide a low signal; a second circuit to provide a high signal, where the high signal has a greater voltage magnitude than the low signal; and a differential amplifier configured to receive the low signal from the first circuit and the high signal from the second circuit. The differential amplifier is for producing an output voltage that is based on the high signal and the low signal. The example circuitry includes a first measurement circuit to measure the output voltage; a second measurement circuit to measure the low signal at the first circuit; and processing logic to determine a differential measurement based on the output voltage measured by the first measurement circuit, the low signal measured by the second measurement circuit, and calibration values obtained for the circuitry.

At least one sound generator operatively coupleable to a corresponding at least one auscultatory sound-or-vibration sensor provides for generating a corresponding at least one sound signal that is applied to the corresponding at least one auscultatory sound-or-vibration sensor. For each sound generator and corresponding auscultatory sound-or-vibration sensor operatively coupled thereto, a communications interface provides for receiving a corresponding auscultatory sound signal from the corresponding auscultatory sound-or-vibration sensor, and at least one computer processor operatively coupled to the communications interface provides for either generating, or causing to be generated, an electronic audio signal that drives the sound generator, causing a corresponding at least one sound signal to be generated thereby, and at least one computer processor provides for analyzing the auscultatory sound signal from the corresponding auscultatory sound-or-vibration sensor responsive thereto for determining whether or not the corresponding at least one auscultatory sound-or-vibration sensor is functioning properly.

An auscultatory sound-or-vibration sensor electronic test signal applied to a sound generator generates an acoustic sound signal, responsive to which an auscultatory sound-or-vibration sensor in proximity to the sound generator generates a corresponding auscultatory sound signal. The auscultatory sound-or-vibration sensor electronic test signal incorporates a plurality of frequency components, each frequency component of which incorporates an integral number of wavelengths and is terminated following a duration of time corresponding to the integral number of wavelengths after that frequency component is applied to the corresponding sound generator. A determination of whether or not the auscultatory sound-or-vibration sensor is functioning properly is made responsive to an analysis of a Fourier Transform of the auscultatory sound signal.

A differential to single-ended buffer amplifier with a swing suppression resistor in the differential amplification architecture is shown. The differential to single-ended buffer amplifier has a positive input terminal, a negative input terminal, a differential to single-ended operational amplifier (DISO op amp), and a swing suppression resistor. The DISO op amp has a non-inverting input terminal and an inverting input terminal respectively coupled to the positive input terminal and the negative input terminal, and it has a single-ended output terminal that outputs the output signal of the differential to single-ended buffer amplifier. The swing suppression resistor is connected between the negative input terminal of the differential to single-ended buffer amplifier and the non-inverting input terminal of the DISO op amp.

An auscultatory sound signal acquired by a recording module is coupled through a high-pass filter having a cut-off frequency in the range of 3 to 15 Hz and subsequently filtered with a low-pass filter. The high-pass filter incorporates a pair of high-pass filter input circuits having a corresponding pair input terminals across which the auscultatory sound signal is operatively coupled, wherein each high-pass filter input circuit is associated with a corresponding input of an electronic differential-input amplifier, for each high-pass filter input circuit, the corresponding input terminal is operatively coupled to a first terminal of a corresponding capacitor, the second terminal of the corresponding capacitor coupled to both the corresponding input of the electronic differential-input amplifier and to a first terminal of a corresponding resistor, and the second terminal of the corresponding resistor is operatively coupled to a circuit ground.

The disclosure provides a time gain compensation (TGC) circuit. The TGC circuit includes an impedance network. A differential amplifier is coupled to the impedance network. The differential amplifier includes a first input port, a second input port, a first output port and a second output port. A first feedback resistor is coupled between the first input port and the first output port. A second feedback resistor is coupled between the second input port and the second output port. The impedance network provides a fixed impedance to the differential amplifier when a gain of the TGC circuit is changed from a maximum value to a minimum value.