Abstract: An amplifier includes an input circuit, an amplification circuit, and at least two feedback circuits. The input circuit is connected with an input end of the amplification circuit; an output end of the amplification circuit is connected with a first end of each of the feedback circuits respectively; a second end of each of the feedback circuits is connected with the input circuit respectively. The input circuit is configured to receive an input signal and a feedback signal; the amplification circuit is configured to amplify the input signal and the feedback signal to obtain an amplified signal. The feedback signal is fed back to the input circuit by feeding back at least a part of the amplified signal through a target feedback circuit; and the target feedback circuit is a feedback circuit that depends on the type of the input signal of the at least two feedback circuits.

Abstract: A spike generation circuit includes a first CMOS inverter connected between a first power supply and a second power supply, an output node of the first CMOS inverter being coupled to a first node that is an intermediate node coupled to an input terminal to which an input signal is input, a switch connected in series with the first CMOS inverter, between the first power supply and the second power supply, a first inverting circuit that outputs an inversion signal of a signal of the first node to a control terminal of the switch, and a delay circuit that delays the signal of the first node, outputs a delayed signal to an input node of the first CMOS inverter, and outputs an isolated output spike signal to an output terminal.

Abstract: An amplifier circuit includes: an operational amplifier that includes two input terminals and an output terminal; a voltage-dividing resistor circuit electrically connected to the output terminal and that includes a voltage-dividing terminal that outputs a potential obtained by voltage-dividing a potential of the output terminal and a feedback resistor circuit electrically connected to the voltage-dividing terminal and one of the two input terminals. The voltage-dividing resistor circuit includes a plurality of resistors that each include terminals and a switch. The plurality of resistors includes a first resistor and a second resistor. The first resistor includes a terminal that corresponds to the voltage-dividing terminal. The switch switches, from a first terminal of the first resistor to a second terminal of the second resistor, the terminal that corresponds to the voltage-dividing terminal.

Abstract: An amplifier circuit includes: an operational amplifier that includes two input terminals and an output terminal; a voltage-dividing resistor circuit electrically connected to the output terminal and that includes a voltage-dividing terminal that outputs a potential obtained by voltage-dividing a potential of the output terminal and a feedback resistor circuit electrically connected to the voltage-dividing terminal and one of the two input terminals. The voltage-dividing resistor circuit includes a plurality of resistors that each include terminals and a switch. The plurality of resistors includes a first resistor and a second resistor. The first resistor includes a terminal that corresponds to the voltage-dividing terminal. The switch switches, from a first terminal of the first resistor to a second terminal of the second resistor, the terminal that corresponds to the voltage-dividing terminal.

Abstract: A management server includes a memory, and at least one processor configured to control an audio client system, by execution of instructions stored in the memory. The at least one processor is configured to acquire a first transfer function measured for a portion of or for all of the first signal path in the audio client system. The at least one processor is also configured to generate a virtual second signal path for a portion of or for all of the first signal path in the audio client system, and calculate a second transfer function for a portion of or for all of the generated virtual second signal path. The at least one processor is also configured to determine a condition of the audio client system, based on a result of a comparison between the first transfer function and the second transfer function.

Abstract: A feedback ammeter, which may be included in a source measure unit or a digital multi-meter, for example, including an operational amplifier having an input and an output and a feedback path electrically coupled between the output and the input of the operational amplifier. The feedback path includes a first non-linear device to allow the measurement of decades of current. The ammeter also includes an amplifier electrically coupled to the input of the operational amplifier and the output of the operational amplifier, a second non-linear device electrically coupled to an output of the amplifier, and a resistor electrically coupled between the second capacitor and the input of the operational amplifier. A constant resistance input impedance is established using the second non-linear device that can adjust the circuit gain.

Abstract: An acoustic transducer includes a controller configured to receive an input audio signal and to generate a first reference signal indicative of an envelope of the input audio signal. The controller is further configured to provide a stationary coil signal to a stationary coil of an acoustic transducer based on the first reference signal and to measure a current through the stationary coil after providing the stationary coil signal to the stationary coil. The controller is further configured to generate a first output indicative of the current through the stationary coil and to determine a magnetic flux in an air gap of magnetic material based on the first output. The controller is further configured to generate a voltage output for a moving coil that is inversely proportional to the magnetic flux in the air gap. The voltage output provides an undistorted output that corresponds to the input audio signal.

Abstract: Aspects of this disclosure relate to an adaptive biasing circuit for a power amplifier. The adaptive biasing circuit can include a shunt resistor arrangement and/or a floating gate linearizer arrangement.

Abstract: Described is an apparatus which comprises: an amplifier to receive a reference voltage; and calibration logic which is operable to receive a first voltage and to provide the reference voltage to the amplifier, wherein the calibration logic is operable to generate a look-up table (LUT) that maps the first voltage to a drive current.

Abstract: The present invention relates to a technical field of microwave heating, and more particularly to a microwave frequency-selective heating device and a method thereof. The microwave frequency-selective heating device includes: a heating chamber with a microwave feed-in device, and a frequency controller; wherein the frequency controller is connected to the microwave feed-in device. According to the microwave frequency-selective heating device and the method of the present invention, the heating frequency is adjusted by setting the microwave adjusting device, which improves a material heating uniformity while greatly increases a material microwave absorption rate, so as to solve a heating efficiency problem of the conventional technologies. According to the present invention, the frequency for the heated material is intelligently selected by the micro-processor of the microwave adjusting device, and then fed in after being adjusted by the frequency control circuit, which is effective and convenient.

Abstract: Systems and methods are provided for improved stability of audio amplifiers that incorporate external speaker connectivity. In one example, a system includes an audio amplifier circuit comprising two or more amplifier stages and a stability resistor and configured to receive an audio input signal, the audio amplifier circuit configured for at least two modes of operation, a first mode having a high input transconductance and the stability resistor is coupled to an output of the audio amplifier circuit, and a second mode having a lower input transconductance and the stability resistor is decoupled from the output of the audio amplifier circuit. The system further includes an amplitude detection circuit configured to provide a signal mode detection signal, an amplifier switching circuit configured to adjust a variable input transconductance of at least one of the amplifier stages, and a load switching circuit configured to couple and decouple the stability resistor at the output of the audio amplifier circuit.

Abstract: An amplifier is configured to amplify an RF signal as between an input terminal and an output terminal across a wideband frequency range. A first LC network is connected to the input terminal and has first and second reactive components. A first switching device is connected between the first and second reactive components and couples both the first and second reactive components to the input terminal in an ON state, and disconnects the second reactive component from the input terminal in an OFF state. A second LC network is connected to the output terminal and has third and fourth reactive components. A second switching device is connected between the third and fourth reactive components and couples both the third and fourth reactive components to the output terminal in an ON state and disconnects the fourth reactive component from the output terminal in an OFF state.

Abstract: A method and a PET apparatus are provided. According to an example of the method, a saturation indicia of a target detector may be determined through simulating emission of a ? photon to the target detector. The target detector is any one of SiPM detectors of a PET apparatus. The saturation indicia is for designating a maximum output voltage after amplifying an output of the target detector through a VGA when one ? photon is received by the target detector. The target VGA is a VGA corresponding to the target detector. By comparing an output voltage of the target VGA and the saturation indicia, it may determine that the target detector received a saturation event if the output voltage of the target VGA is higher than the saturation indicia. An amplifier gain of the target VGA may be adjusted until an amount of the saturation events detected by the target detector in unit time satisfies a pre-determined threshold.

Abstract: Provided is an imaging apparatus, including: a vertical scanning circuit configured to output the reset signal and the image signal sequentially from each of a plurality of pixels by selecting the plurality of pixels sequentially; and an amplifier unit configured to output a plurality of image signals obtained by amplifying one image signal that is output from one of the plurality of pixels at a plurality of gains including a first gain and a second gain, in which, in a reading period, which is a period between selection of a first pixel by the vertical scanning circuit out of the plurality of pixels and subsequent selection of a second pixel out of the plurality of pixels, a number of times the amplifier unit is reset is less than a number of the plurality of amplified image signals.

Abstract: In a state that a plurality of capacitances are connected between input and output nodes of an amplifier, a short circuit is established between the input and output nodes of the amplifier. In a state that at least one of the capacitances is isolated from the input and output nodes of the amplifier, the plurality of capacitances are connected to the input and output nodes of the amplifier, in a case that an output from the amplifier is larger than a threshold.

Abstract: The present disclosure provides an amplifier and associated methods of operations. An exemplary amplifier an input terminal; an output terminal; a first virtual ground node; a second virtual ground node; an operational amplifier coupled with the input terminal and the output terminal; a resistive input section coupled with an input of the operational amplifier; and a resistive feedback section coupled with an output of the operational amplifier. The resistive input section includes a fixed input resistor coupled with the input terminal and the first virtual ground node, and a switchable input resistor segment coupled with the fixed input resistor in parallel. The resistive feedback section includes a fixed feedback resistor coupled with the output terminal and the first virtual ground node, and a switchable feedback resistor segment coupled with the fixed feedback resistor in parallel.

Abstract: Provided is a programmable gain amplifier that includes controlled gain steps that dynamically control an output voltage in real-time. The programmable gain amplifier includes a first transistor and a second transistor that includes respective control ports, input ports, and output ports. The programmable gain amplifier also includes a resistor connected to the output ports of the transistors. Further, at least a third transistor is connected to the output ports, in parallel with the resistor. On applying a control voltage to the third transistor and applying an input voltage to the first control port, the second control port is selectively modified by the control voltage to produce a desired output at the first input port and the second input port.

Abstract: The present invention discloses a gain control circuit capable of easing leakage current influence. According to an embodiment of the present invention, the gain control circuit comprises: at least one signal input end for receiving at least one input signal; a signal output end for outputting an output signal; an amplifier coupled between an amplifier input end and the signal output end; and a plurality of gain schemes. Each of the gain schemes is set between the at least one signal input end and the signal output end; and when one of the gain schemes is activated to generate the output signal, the rest gain schemes are inactivated to stop gain production and concurrently discharge leakage currents through their respective grounding paths.

Abstract: A variable gain amplifier includes: a first input terminal, a second input terminal and an output terminal; an operational amplifier; a first resistor interposed between the first input terminal and an inverted input terminal of the operational amplifier; second and third resistors interposed between the inverted input terminal and the output terminal; and a fourth variable resistor having a first terminal connected to a node between the second resistor and the third resistor and a second terminal connected to the non-inverted input terminal, wherein the fourth variable resistor includes a resistance pass including a resistor and a switch.

Abstract: A reference voltage generation circuit has: a first PN junction element; a second PN junction element having a higher forward direction voltage than the first PN junction element; a first differential amplifier inputting an anode of the first PN junction element and a first connection node between a first and a second resistor disposed in series between a first output of the first differential amplifier and a first potential, and generating a first output voltage at the first output; and a second differential amplifier inputting an anode of the second PN junction element and a second connection node between a fourth and a third resistor disposed in series between a second output of the second differential amplifier and the first output of the first differential amplifier, and generating a reference voltage at the second output. A resistance ratio between the third and the fourth resistors is variable.

Abstract: A programmable gain amplifier (PGA) includes an op amp, an input circuit, a feedback circuit, and a calibration circuit. The input circuit is connected between a PGA input node and an op-amp input node and selectively applies the analog input signal to the op-amp input node. The feedback circuit is connected between an op-amp output node and the op-amp input node and applies the amplified analog output signal as a feedback signal to the op-amp input node. The calibration circuit is connected between a calibration reference node and the op-amp input node and selectively connects the calibration reference node directly to the op-amp input node without traversing any of the input circuit. The PGA may be implemented as a single-ended or differential amplifier. The PGA avoids reduced linearity resulting from series combinations of switches in the input circuit when configured for its normal operating mode.

Abstract: A device comprises a first amplifier, a first resistive element that comprises a first resistor and a first dummy switch, a second amplifier, a second resistive element that comprises a second resistor and a second dummy switch, and a programmable resistive gain element operable to receive control input, wherein a resistance value of the programmable resistive gain element is based at least in part on the received control input, wherein a first end of the programmable resistive gain element is connected to both the first inverting input of the first amplifier and to a second end of the first dummy switch, and wherein a second end of the programmable resistive gain element is connected to both the second inverting input of the second amplifier and to a second end of the second dummy switch.

Abstract: According to some embodiments, a switch having an “on” state and an “off” state is exhibiting a low impedance in the “on” state, and a very high impedance in the “off” state. The switch comprises three series MOS transistors, the first transistor having its drain connected to the input. The switch also comprises additional circuitry which reduces, in the “off” state, the leakage current of the MOS transistor connected to the input of the switch by connecting its source and bulk to an electrical node replicating the voltage of the input node. According to some embodiments, the said switch is used in a voltage amplifier for capacitive sensing devices, such as MEMS gyroscopes and MEMS microphones; the voltage amplifier uses an operational amplifier used in a trans-capacitance configuration, with the feedback path comprising the said switch and a capacitor, wherein the said switch is connected to the input of, the voltage amplifier.

Abstract: A high performance digitalized Programmable Gain Amplifier (PGA). In prior art circuit, a dual-ladder DAC is employed for gain control, the back gate leakage of NMOS resistors in the fine ladder conquers fine ladder nominal current and it produces non-monotonic gain scallop. Two new art design techniques: (1) adaptively control the fine ladder; and (2) use dummy PMOS brunch device leakage compensates for the NMOS resistor device leakage, are proposed so that the non-monotonic scallops are substantially eliminated and 13-bit resolution/accuracy PGA has been achieved.

Abstract: An apparatus for limiting the bandwidth of an amplifier provides for the design of an input impedance, a feedback impedance, and a load impedance such that the load impedance is proportional to the sum of the input impedance and feedback impedance. A sampling circuit has a load impedance including a resistor and capacitor in series to reduce the effective amplifier transconductance, which decreases bandwidth without increasing noise density or making this circuit more difficult to drive than a conventional circuit.

Abstract: A first trimming capacitor having a first terminal and a second terminal is coupled in parallel between a first terminal and a second terminal of a first capacitor. The first trimming capacitor comprises a first plurality of switched capacitors having different capacitances coupled in parallel. Each of the switched capacitors comprises a switch capacitor and a switch coupled in series. In an illustrative application the first capacitor and the first trimming capacitor are coupled between an output terminal of an operational amplifier (op-amp) and an inverting input terminal of the op-amp. A second capacitor and a second trimming capacitor similar to the first capacitor and the first trimming capacitor are coupled between an input and the inverting input terminal of the op-amp.

Abstract: A variable gain amplifier circuit is provided. The circuit includes an operational amplifier for amplifying and outputting an input signal according to a cutoff frequency and a gain, a feedback resistor for changing a first resistance according to a first digital control code value which determines the cutoff frequency, and an input resistor for changing a second resistance according to a second digital control code value which is determined based on a difference of the first digital control code value and a gain code value. The gain is determined by a ratio of the first resistance and the second resistance and linearly changes on a decibel (dB) basis according to the first digital control code value, the cutoff frequency is inversely proportional to the first resistance and linearly changes on a log scale, and the variable gain can be easily set using the control code.

Abstract: A semiconductor device includes: an amplifier circuit that has an inverting input terminal, a non-inverting input terminal, and an output terminal; a first variable voltage source that generates a first bias voltage having a voltage value corresponding to a first set value; a second variable voltage source that generates a second bias voltage having a voltage value corresponding to a second set value; a first resistor whose one end is connected to the inverting input terminal; a second resistor that is connected between the output terminal and the inverting input terminal; a third resistor whose one end is connected to the non-inverting input terminal; and a fourth resistor that is connected between the second variable voltage source and the non-inverting input terminal. The first bias voltage is provided to the other end of the first resistor. An input signal is provided to the other end of the third resistor.

Abstract: Embodiments of the invention described herein provide a magnetic sensor interface capable of adjusting signal conditioning dynamically using a speed signal of a target such that the true positive and negative peaks of the input signal are maintained for the given target across its entire speed range (0-Max rpm), therefore increasing the signal to noise ratio at low speeds and avoiding clipping or distortion at high speeds. In one aspect, a method comprises receiving an alternating differential voltage signal from a sensor. The differential voltage signal has an amplitude that changes relative to a change in speed of a target. The alternating differential voltage signal is converted to an attenuated single-ended voltage signal that can be dynamically scaled. The attenuated single-ended voltage signal can be scaled by multiplying the attenuated single-ended voltage signal by a scaling factor.

Abstract: A reconfigurable network arrangement of resistors and switches is constructed so that it can be coupled to one or more operational amplifiers and selectively programmed so as to set the gain of the resulting amplifier. The configuration of the network arrangement of resistors and switches to include resistors that can be connected in the feedback path in series and in parallel with each other is such as to provide a wider selection of gain settings, without the need to increase the physical area of the switches on a integrated circuit arrangement.

Abstract: An adjustable gain audio power amplifying circuit includes an input unit, an audio amplifying unit connected to the input unit, a gain adjusting unit connected to the audio amplifying unit, a controlling unit connected to the gain adjusting unit, a comparing unit connected between the gain adjusting unit and the controlling unit and an output unit connected to the audio amplifying unit. The comparing unit compares an outputted signal of the output unit with a common-mode reference voltage, outputs a gain adjustment controlling signal and sends the gain adjustment controlling signal into the controlling unit. When the outputted signal equals the common-mode reference voltage, the gain adjustment controlling signal turns over and then the controlling unit detects the turnover and sends a received gain adjustment signal into the gain adjusting unit. Based on the received gain adjustment signal, the gain adjusting unit controls gains of the adjustable gain audio power amplifying circuit.

Abstract: Provided is an analog amplifier for amplifying an analog signal and an analog filter, and in particular, an apparatus and method for controlling gain and cutoff frequency of the variable gain amplifier and the variable cutoff frequency filter that is capable of changing the gain and cutoff frequency. The variable resister includes a plurality of resister segments in the variable resister and, when a plurality of resistance candidates for the variable resister are arranged in order of size, the resistance candidates form a geometric series.

Abstract: An electronic device comprising an amplifier having at least a first input transistor of a first doping type. A first transistor is coupled with a channel as a feedback path between an output of the amplifier and a control gate of the first input transistor forming an input of the amplifier. A diode-coupled second transistor is coupled with a channel between a first current source and the output of the amplifier wherein a control gate of the first transistor is coupled between the first current source and the diode-coupled second transistor and the first transistor is of a second doping type which is opposite to the first doping type of the first input transistor of the amplifier.

Abstract: Provided is a variable gain amplifier. The variable gain amplifier includes an operational amplifier, a variable feedback impedance unit, a variable compensation impedance unit, and a variable current source. The variable feedback impedance unit is connected between an inverting input terminal and output terminal of the operational amplifier, and has a feedback impedance value which varies for gain control. The variable compensation impedance unit is connected to the inverting input terminal, and has a compensation impedance value which varies in response to change of the feedback impedance value for maintaining a constant feedback factor. The variable current source is connected to the inverting input terminal, and supplies an output current, which varies in response to change of the compensation impedance value, to the variable compensation impedance unit.

Abstract: A variable gain amplifier, to amplify an audio input signal to output an audio output signal at an adjustable gain, includes an operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal to output the audio output signal; an attenuation-rate adjustable feedback circuit to feed back the audio output signal from the output terminal of the operational amplifier to the inverting input terminal of the operational amplifier as a feedback signal, and attenuate the audio output signal and output the feedback signal to the inverting terminal; and an attenuation-rate adjustable attenuator to attenuate the audio input signal for output it as an attenuated signal to the non-inverting input terminal of the operational amplifier. Settings of the attenuation rates of the feedback circuit and the attenuator are combined and a resolution of level of the audio output signal is increased.

Abstract: A trans-impedance amplifier (TIA) with an adjustable bandwidth is disclosed. The TIA of the present invention includes the amplifying stage and the emitter follower stage arranged in the downstream of the amplifying stage. The transistor in the amplifying stage includes a diode in the emitter thereof to provide a substantial emitter level to the transistor. This diode is biased by another current source with a variable function. The operating point of the diode, in particular, the differential resistance thereof, is variable by the current source, which adjusts the bandwidth of the TIA without affecting the phase characteristic of the TIA.

Abstract: A temperature dependence adjustable operational amplifier circuit which suppresses a change in a gain caused by a change in an input voltage is provided. In an operational amplifier including a first input terminal and an output terminal, an operational amplifier having an inverting input terminal and a non-inverting input terminal, an input resistance circuit, and a feedback resistance circuit, each of the input and feedback resistor circuits has a resistor and a trimming resistor, which are different in temperature coefficient from each other, connected in series with each other, and a source-drain path of a MOS transistor included in the trimming resistor circuit is disposed between resistance and an inverting input terminal, and a substrate potential thereof is set to a potential of the inverting input terminal of the operational amplifier.

Abstract: A differential amplifier comprises a first amplifier (A1) with a signal input (Inp) and a signal output (Out1) that is fed back to a first feedback input (In1) of the first amplifier (A1) and is also connected to a first output (outp) of the differential amplifier. Furthermore, a buffer circuit (Buff) is connected to the first output (outp). A nonlinear resistor circuit (Rnl1, Rnl2) is coupled via a first output node (Vmid1) with the first output (outp) and via a second output node (Vmid2) with the buffer circuit (Buff).

Abstract: Techniques are disclosed for canceling an offset component (e.g., dc component or dc offset) in an amplifier circuit. For example, an apparatus comprises an amplifier circuit with an amplifier element and a feedback resistor network coupled between an output of the amplifier element and an input of the amplifier element. The apparatus also comprises a current source coupled to the feedback resistor network, the current source generating a current signal that generates a voltage in a first portion of the feedback resistor network that cancels an offset component present in an input signal received by the amplifier circuit. A second portion of the feedback resistor network may be adjustable so that a gain applied to the input signal is adjustable while the offset component is canceled from the input signal. One or more resistors in the feedback resistor network may be composed of the same or substantially similar material as one or more resistors associated with the current source.

Abstract: A variable gain analog amplifier is described that uses pulse-density modulation in the form of a sigma-delta modulator (SDM) to produce a gain by modulating the selection of a switch that selects the amount of resistance in a negative feedback loop of the amplifier. The output of the SDM is dithered to increase the gain resolution of the analog amplifier, wherein the increased resolution produces a quiet, inaudible transition between changes in gain setting at an output of the variable gain amplifier and in addition produces a quiet, inaudible mixing and merging of audio signals..

Abstract: A variable gain amplifier includes an integrator having an input, an output and a feedback loop connected between the input and output, a plurality of input chains connected in parallel between the amplifier input and the input of the integrator, each input chain including a resistor and a first switch and a plurality of second switches, each second switch connected between an intermediate node between the resistor and first switch of a respective input chain and the feedback loop of the integrator, wherein the resistance of the resistors in the input chains is scaled by a scaling factor with respect to one another and the on-resistances of the first and second switches connected to each intermediate node are scaled by the corresponding scaling factor.

Abstract: An amplifier circuit and method are described for linearizing the gain of a voltage or current feedback amplifier that is non-linear.

Abstract: System and method for common mode translation in continuous-time sigma-delta analog-to-digital converters. An embodiment includes a loop filter having an RC network coupled to a differential signal input, a Gm-C/Quantizer/DAC circuit (GQD) coupled to the loop filter, a common-mode level adjust circuit coupled to signal inputs of the GQD, and a tuning circuit coupled to the GQD and the common-mode level adjust circuit. The GQD evaluates an input signal provided by the RC network. computes a difference between a filtered input signal and the feedback quantization signal to generate an error signal, measures the error signal, and compensates for the error signal with sigma-delta noise-shaping. The common-mode level adjust circuit alters a common-mode level of a differential input signal to be substantially equal to a desired common-mode level and the tuning circuit provides a compensation voltage to the common-mode level adjust circuit based on a difference between the common-mode levels.

Abstract: A temperature dependence adjustable operational amplifier circuit which suppresses a change in a gain caused by a change in an input voltage is provided. In an operational amplifier including a first input terminal and an output terminal, an operational amplifier having an inverting input terminal and a non-inverting input terminal, an input resistance circuit, and a feedback resistance circuit, each of the input and feedback resistor circuits has a resistor and a trimming resistor, which are different in temperature coefficient from each other, connected in series with each other, and a source-drain path of a MOS transistor included in the trimming resistor circuit is disposed between resistance and an inverting input terminal, and a substrate potential thereof is set to a potential of the inverting input terminal of the operational amplifier.

Abstract: A programmable device includes an operational amplifier and circuitry. The operational amplifier is configured to generate an output voltage based on input voltages at input terminals thereof. The circuitry is configured to provide the input voltages to the operational amplifier. The configuration of the circuitry allows the programmable device to implement discrete-time or continuous-time functions. The circuitry includes a resistor network and a capacitor network configured to be selectively coupled to the operational amplifier.

Abstract: A variable gain amplifier circuit (200) comprising an amplifier element (202) having an input (208, 210) and an output (220, 222); a feedback loop (224, 226) having a feedback impedance (228, 230) connected between the input (208, 210) and output (232, 234) of the amplifier element (202); an input branch (212, 214) having an input resistance connected between an input of the variable gain amplifier circuit and the input (208, 210) of the amplifier element (202); and a plurality of switches for selecting a gain of the variable gain amplifier circuit (200); characterised in that the variable gain amplifier circuit (200) further comprises an intermediate element (204) having an input and an output, the input being connected to a node between one of the switches and the feedback impedance (228, 230), such that the output can provide a signal which can be used to attenuate a signal component in the output (220, 222) of the amplifier element (202) caused by a non-linearity in the plurality of switches.

Abstract: Techniques are disclosed for canceling an offset component (e.g., dc component or dc offset) in an amplifier circuit. For example, an apparatus comprises an amplifier circuit with an amplifier element and a feedback resistor network coupled between an output of the amplifier element and an input of the amplifier element. The apparatus also comprises a current source coupled to the feedback resistor network, the current source generating a current signal that generates a voltage in a first portion of the feedback resistor network that cancels an offset component present in an input signal received by the amplifier circuit. A second portion of the feedback resistor network may be adjustable so that a gain applied to the input signal is adjustable while the offset component is canceled from the input signal. One or more resistors in the feedback resistor network may be composed of the same or substantially similar material as one or more resistors associated with the current source.

Abstract: An amplifier system can include a feedback amplifier circuit having an amplifier, a feedback capacitor connected between an input terminal and an output terminal of the amplifier by at least one first switch, and a reset capacitor connected across the feedback capacitor by at least one second switch and between a pair of reference voltages by at least one third switch. During an input-signal processing phase of operation, a control circuit may close the at least one first switch and open the at least one second switch to electrically connect the feedback capacitor between the input and output terminals to engage feedback processing by the feedback amplifier circuit, and close the third switch to electrically connect the reset capacitor between the first and second voltages to charge the reset capacitor to a selectable voltage difference.

Abstract: An automatic gain control circuit including a variable gain amplifier (11) adapted to receive a received signal (R) and to output an amplified signal (A) to an analog to digital converter (20), and a gain controller (12) which is connected to said variable gain amplifier (11) for receiving said amplified signal (A) and for controlling a gain of said variable gain amplifier (11). The gain controller (12) is adapted to determine an occurrence of a threshold event each time the amplified signal (A) has reached a predetermined threshold, decrease the gain of the variable gain amplifier (11) at each occurrence of a threshold event, measure a delay since the last threshold event, increase the gain of the variable gain amplifier (11) if the delay is greater than a delay specified value and if the gain of the variable gain amplifier (11) is not maximum.

Abstract: The exemplary embodiments provide a method, system, and device for identifying chemical species in a sample. According to one embodiment, the method, system, and device may include introducing a sample gas into a differential ion mobility device, ionizing at least a portion of the sample gas to generate at least one ion species, filtering the at least one ion species between a pair of filter electrodes, generating a detection signal in response to the at least one ion species depositing a charge on a collector electrode, and detecting a spectral peak associated with the at least one ion species.