Abstract: An impedance measurement system including: a signal generator including a memory and arranged to generate a digital test signal and at least one digital demodulation signal based on the memory, wherein the digital test signal has a first frequency and the at least one digital demodulation signal has the first frequency; a single pin for providing to a Device Under Test (DUT), an analogue test signal based on the digital test signal and measuring, in response to providing the analogue test signal to the DUT, an analogue input signal; and a demodulator configured to obtain: a first filtered digital signal based on the input signal; and the at least one digital demodulation signal to produce at least one digital demodulated signal indicative of the impedance.

Abstract: An amplifier (V) for an integrated circuit amplifier circuit (IC) having a switched capacitor circuit (Cs, Cf) includes a capacitor for frequency compensation (CC1) that is connected in parallel to an amplifier stage (V2). This amplifier is advantageous because at least one second capacitor for frequency compensation (CC2) is selectively connected in parallel to the first capacitor for frequency compensation (CC1) via a switch controlled by a capacitor switching signal (clk).

Abstract: An amplifier (V) for an integrated circuit amplifier circuit (IC) having a switched capacitor circuit (Cs, Cf) includes a capacitor for frequency compensation (CC1) that is connected in parallel to an amplifier stage (V2). This amplifier is advantageous because at least one second capacitor for frequency compensation (CC2) is selectively connected in parallel to the first capacitor for frequency compensation (CC1) via a switch controlled by a capacitor switching signal (clk).

Abstract: The invention relates to a compensation circuit (1–6) to compensate nonlinear distortions of an A/D converter comprising a signal input and a compensation system. In order to avoid the high costs related to the complex analog design of the A/D converter and/or the high energy consumption in this converter and compensation system, it is proposed that a compensation circuit be used that is composed of digital circuit elements that are connected following the A/D converter and which has a nonlinearly distorted output signal of the A/D converter supplied to it to compensate the nonlinear distortion. Adaptive coefficients are preferably employed here for the compensation.

Abstract: An at least second-order active filter circuit includes an operational amplifier (Op) whose frequency response, in conjunction with an RC network (R1, R2, C1, C2), serves to set a predetermined low-pass characteristic. The frequency response of the operational amplifier (Op) forms an integral part of this low-pass characteristic.

Abstract: An at least second-order active filter circuit includes an operational amplifier (Op) whose frequency response, in conjunction with an RC network (R1, R2, C1, C2), serves to set a predetermined low-pass characteristic. The frequency response of the operational amplifier (Op) forms an integral part of this low-pass characteristic.

Abstract: The invention relates to a compensation circuit (1-6) to compensate nonlinear distortions of an A/D converter (A/D: analog-to-digital) comprising a signal input and a compensation system.

Abstract: An at least second-order active filter circuit includes an operational amplifier (Op) whose frequency response, in conjunction with an RC network (R1, R2, C1, C2), serves to set a predetermined low-pass characteristic. The frequency response of the operational amplifier (Op) forms an integral part of this low-pass characteristic.

Abstract: A pulse-width-modulated DC-DC converter provides an output signal that is feedback to an error amplifier. The converter includes a comparator for comparing the output voltage of the error amplifier with the output voltage of a compensated ramp generator and having its output coupled to a switching transistor. The compensated ramp generator is designed so that the signal proportional to the current (IDrossel) through an inductor is superimposed on the ramp voltage so as to generate an output voltage having a sawtooth waveform with a concave rise.

Abstract: An at least second-order active filter circuit includes an operational amplifier (Op) whose frequency response, in conjunction with an RC network (R1, R2, C1, C2), serves to set a predetermined low-pass characteristic. The frequency response of the operational amplifier (Op) forms an integral part of this low-pass characteristic.

Abstract: An amplifier has a first amplifier stage with a first input terminal to which an input signal is applied and with an output terminal that is connected to an input terminal of a second amplifier stage located downstream. The second amplifier stage provides an output signal that is fed back to a second input terminal of the first amplifier stage through a feedback path, which preferably contains a passive network. The amplification of this combination of the first and second amplifier stages with feedback depends essentially on the parameters of the network in the feedback path. The amplifier according to the invention also has a noise source that is connected in parallel with the first amplifier stage, and is also connected to the input terminal of the second amplifier stage. The level of a signal component at the output of the second amplifier stage depends on the parameters of the network in the feedback branch and the amplification of the first amplifier stage.

Abstract: A DC/DC converter including a switching transistor, an inductor, a smoothing capacitor, and a switching element which are connected so as to convert an input voltage U.sub.E to an output voltage U.sub.A greater or less than the input voltage U.sub.E. The current through the inductor can be measured by providing a comparator having a first input connected to the switching transistor, and a second input connected to a reference transistor and a reference current source so as to fix the switching threshold of the comparator at the second input.

Abstract: An integrated driver circuit for driving different capacitive loads, which includes a setting element. The setting element develops a setting signal S for a given numerical measure signal M. The numerical measure signal M is developed by an input device, which is coupled to the setting element. The numerical measure signal M corresponds to one of the different capacitive loads which is driven by the driver circuit. Coupled to the setting element is an output stage, which provides an output current that corresponds to the setting signal S.

Abstract: A semiconductor structure for creating resistor networks, particularly ladder networks, has resistive sections made of semiconductor material and metal contact areas. A continuous semiconducting resistor strip is provided as a primary arm. Along this continuous primary arm, metal contact areas which contact the resistor strip at the side are provided in accordance with the desired resistor ratio and in order to form corresponding series resistors. In a ladder network, shunt arms have one end connected directly to the long side of the primary arm via the semiconductor material. At the other end of each of the shunt arms, a respective metal contact area is provided.

Abstract: The invention relates to a digitally adjustable crystal oscillator having a quartz crystal and a monolithic integrated oscillator circuit including a series combination of a first frequency-adjusting capacitor C1 and a second frequency-adjusting capacitor C2 connected in parallel with the quartz crystal and comprising parallel-connected first capacitance stages and parallel-connected second capacitance stages, respectively, and an inverter circuit connected in parallel with the quartz crystal and comprising a feedback resistor R.sub.K, the output of the innverter circuit being connected to a load resistor. The inverter circuit comprises parallel-connected inverter stages, and switching elements are provided within the inverter stages and cqapacitor stages in such a way that a respective one of the inverter stages as well as a first capacitance stage C.sub.1i and a second capacitance stage C.sub.2i are switchable into or out of circuit by means of a control signal I.sub.i.