The invention describes a method of performing analog-to-digital conversion on an input signal (P.sub.in) within a range (R1) using a sigma-delta modulator (1) comprising a feedback digital-to-analog conversion arrangement (12, 120), which method comprises the steps of: obtaining an amplitude estimate (E1, E2, E3, E4) of the input signal (P.sub.in); defining a subsequent subrange (R2, R3, R4) on the basis of the amplitude estimate (E1, E2, E3); and adjusting operation parameters of the feedback digital-to-analog conversion arrangement (12, 120) on the basis of the subsequent subrange (R2, R3, R4); whereby the method steps are repeated a predefined number of iterations (N). The invention further describes a sigma-delta modulator (1), an analog-to-digital converter (50), and a monitoring device (5) for monitoring an analog input signal (P.sub.in).

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.

Certain aspects of the present disclosure provide amplifiers. Certain aspects of the present disclosure provide methods and apparatus for protecting an such amplifiers, for example an audio amplifier, or a delta-sigma modulator from saturation. One example amplifier generally includes an output stage comprising a plurality of transistors; and a feedback network having an input coupled to an output of the output stage and comprising a plurality of integrators connected in series. At least one of the plurality of integrators generally includes an operational amplifier having an input and an output, a first resistive element coupled to the input of the operational amplifier, a capacitive element coupled between the input and the output of the operational amplifier; and a first switch coupled between the input and the output of the operational amplifier. For certain aspects, the amplifier may be a class-D amplifier or a direct digital feedback amplifier (DDFA).

Methods and systems for thermal image sensing are disclosed. A method involves controlling a current (I.sub.ACT) from a detector of a thermal image sensor with a first pulse width modulated (PWM) signal (PWM.sub.ACT) for gain control, controlling a current (I.sub.REF) from a reference source of the thermal image sensor with a second PWM signal (PWM.sub.FEEDBACK) for gain control and for offset correction, wherein the second PWM signal (PWM.sub.FEEDBACK) is generated in response to a digital output (D.sub.Q) that is fed back from an analog to digital conversion circuit, and providing a current (I.sub.SUM), which is the sum of the current (I.sub.ACT) and the current (I.sub.REF), to the analog to digital conversion circuit.

The invention describes a method of performing analog-to-digital conversion on an input signal (P.sub.in) within a range (R1) using a sigma-delta modulator (1) comprising a feedback digital-to-analog conversion arrangement (12, 120), which method comprises the steps of: obtaining an amplitude estimate (E1, E2, E3, E4) of the input signal (P.sub.in); defining a subsequent subrange (R2, R3, R4) on the basis of the amplitude estimate (E1, E2, E3); and adjusting operation parameters of the feedback digital-to-analog conversion arrangement (12, 120) on the basis of the subsequent subrange (R2, R3, R4); whereby the method steps are repeated a predefined number of iterations (N). The invention further describes a sigma-delta modulator (1), an analog-to-digital converter (50), and a monitoring device (5) for monitoring an analog input signal (P.sub.in).

A low power consumption sigma-delta modulator architecture capable of dynamic detection of output signal strength to change dynamic range, a method for implementing low power consumption circuit thereof, and a method for automatically correcting and extending dynamic range of the sigma-delta modulator are provided. An automatic correction unit is utilized to detect system output signal strength of the sigma-delta modulator, compare system input signal specifications to come out multiple sets of dynamic range curves, and thereby extract an appropriate combination of system order and feed-forward coefficients so as to extend the system dynamic range. The circuit architecture of the automatic correction unit is in a digital circuit form, including a digital signal processor, a counter and register array, a comparator, a digital coefficient controller, a feed-forward gain control unit and a system order control unit.

A low power consumption sigma-delta modulator architecture capable of dynamic detection of output signal strength to change dynamic range, a method for implementing low power consumption circuit thereof, and a method for automatically correcting and extending dynamic range of the sigma-delta modulator are provided. An automatic correction unit is utilized to detect system output signal strength of the sigma-delta modulator, compare system input signal specifications to come out multiple sets of dynamic range curves, and thereby extract an appropriate combination of system order and feed-forward coefficients so as to extend the system dynamic range. The circuit architecture of the automatic correction unit is in a digital circuit form, including a digital signal processor, a counter and register array, a comparator, a digital coefficient controller, a feed-forward gain control unit and a system order control unit.

For a radio frequency (RF) receiver system (1) for providing magnetic resonance (MR) information from an examination space of a MR imaging system, a solution for increasing the dynamic range of the radio frequency (RF) receiver system (1) for a better imaging performance shall be created. A sigma delta ADC of the RF receiver system operates in single-bit mode with an automatic gain control (AGC) circuit used to control the DAC feedback strength thereby extending the dynamic range of the receiver to match the MRI signal. The present invention also refers to a magnetic resonance (MR) imaging system, a method A method for extending the dynamic range of a radio frequency (RF) receiver system, a software package for a magnetic resonance (MR) imaging system, a software package for upgrading a magnetic resonance (MR) imaging system and a computer program product.

A sensing circuit for an electrochemical sensor includes a digital-to-analog converter (DAC), an operational amplifier, an instrumentation amplifier, and an analog-to-digital converter (ADC). The DAC generates a biased ground voltage signal which is received by the operational amplifier. The operational amplifier creates a high current biased voltage on one of a pair of terminals connected to the electrochemical sensor. The instrumentation amplifier receives a signal from the pair of terminals, and generates an output representative of a voltage across the pair of terminals with reference to the high current biased ground voltage signal. The ADC converter receives the output and derives an actual voltage reading taken by the electrochemical sensor.

The present invention provides a delta-sigma ADC, wherein the delta-sigma ADC includes an adder, a loop filter, a quantizer, a DAC and a reference voltage compensator. The adder is configured to subtract a feedback signal from an input signal to generate a first signal. The loop filter is configured to receive the first signal to generate at least one filtered signal. The quantizer is configured to generate a digital output signal according to the at least one filtered signal. The DAC is configured to perform a digital-to-analog conversion operation on the digital output signal to generate the feedback signal. The reference voltage compensator is configured to compensate a reference voltage to generate an adjusted reference voltage according to the digital output signal, wherein the adjusted reference voltage is used by the DAC to perform the digital-to-analog conversion operation on the digital output signal to generate the feedback signal.