This invention discloses an active load generation circuit and a filter. The active load generation circuit includes a transistor, a voltage control circuit, a voltage offset and tracking circuit, and a temperature sensing circuit. The transistor provides an impedance and includes a control terminal and an input terminal. The control terminal receives a control voltage, the input terminal receives an input signal, and the impedance is associated with the control voltage. The voltage control circuit generates an intermediate voltage according to a power supply voltage and a first reference voltage. The voltage offset and tracking circuit generates the control voltage according to the input signal and the intermediate voltage such that the control voltage varies with the input signal. The temperature sensing circuit senses an ambient temperature of the active load generation circuit and adjusts the first reference voltage according to the ambient temperature.

Systems and methods for a tunable impedance are provided. A tunable impedance includes a transistor assembly having two terminals and a control input. The transistor assembly includes one or more transistors electrically connected between the two terminals to provide a first impedance between the two terminals, based upon a control signal. One or more replica transistors react to the control signal in a similar fashion as the transistor assembly, to provide a replica impedance based upon the control signal. A control circuit is configured to generate the control signal based upon a voltage across the replica transistor(s) and/or a current through the replica transistor(s).

An electronically controllable resistor (ECR) designed for changing the resistance of a portion of a circuit comprises a voltage converter, a subtractor, an instrumental resistor (IR), and an executive element (EE) which can include at least one MOSFET or IGBT or a vacuum tube. There are a high-potential and two control voltage sources. The converter, which can use logarithmic amplifiers or be digital, is adapted to multiply the high-potential voltage by one of the control voltages and divide by another one. The resulting intermediate voltage is applied to the subtractor and compared therein with a voltage drop on the IR created by the current flowing through the IR and the EE. Thus, the ECR resistance can be regulated. The ECR makes it possible to achieve a wide range of resistance values, down to ultra-small values, while maintaining tolerance to destabilizing factors, including temperature. Also claimed is an ECR control circuit.

A tunable impedance simulator and impedance multiplier circuit and a system for configuring a second generation voltage-mode conveyor circuit (VCII) as the tunable impedance simulator and impedance multiplier are described. The tunable impedance simulator and impedance multiplier circuit includes one VCII having a positive input terminal connected to a voltage source, a negative input terminal connected to the voltage source, and an impedance terminal Z.sub.0 . The impedance terminal Z.sub.0 can be either positive or negative. When the impedance terminal Z.sub.0 is positive, a positive active inductor, a positive capacitance multiplier, and a positive resistance multiplier may be implemented. When the impedance terminal Z.sub.0 is negative, a negative active inductor, a negative capacitance simulator, and a negative resistance simulator may be implemented.

Techniques for linearizing a field effect transistor (FET) are provided. In an example, a method can include averaging a voltage at a drain node of the FET and a voltage at a source node of the FET to provide an average voltage, and applying the average voltage to a gate node of the FET.

Techniques for linearizing a field effect transistor (FET) are provided. In an example, a method can include averaging a voltage at a drain node of the FET and a voltage at a source node of the FET to provide an average voltage, and applying the average voltage to a gate node of the FET.

A resistive attenuator and a method for improving linearity of the resistive attenuator are provided. The resistive attenuator includes a first transistor, an attenuation circuit and a compensation circuit, wherein both the first transistor and the attenuation circuit are coupled between an input terminal and an output terminal of the resistive attenuator, and the compensation circuit is coupled to the first transistor. The first transistor is configured to provide a first signal path between the input terminal and the output terminal. The attenuation circuit is configured to provide a second signal path between the input terminal and the output terminal, wherein signal attenuation of the second signal path is greater than signal attenuation of the first signal path. The compensation circuit is configured to compensate nonlinear distortion caused by the first transistor.

This invention discloses an active load generation circuit and a filter. The active load generation circuit includes a transistor, a voltage control circuit, a voltage offset and tracking circuit, and a temperature sensing circuit. The transistor provides an impedance and includes a control terminal and an input terminal. The control terminal receives a control voltage, the input terminal receives an input signal, and the impedance is associated with the control voltage. The voltage control circuit generates an intermediate voltage according to a power supply voltage and a first reference voltage. The voltage offset and tracking circuit generates the control voltage according to the input signal and the intermediate voltage such that the control voltage varies with the input signal. The temperature sensing circuit senses an ambient temperature of the active load generation circuit and adjusts the first reference voltage according to the ambient temperature.

An electronic device including at least: a reference resistor; two first terminals between which the reference resistor is connected, and two second terminals between which a modified impedance value of the reference resistor is intended to be obtained; a first circuit configured to apply between the two second terminals a voltage substantially equal to that between the two first terminals; a second circuit configured to flow between the two second terminals a second current the value of which corresponds to a fraction of a first current for flowing in the reference resistor between the two first terminals.

A method and system of providing an active differential resistor. The active differential resistor includes a diode having a first node and a second node. There is a capacitor coupled in series between the first node of the diode and an input of the active differential resistor. There is a current source coupled across the first node and the second node of the diode and configured to forward bias the diode such that a Johnson-Nyquist noise of the active differential resistor is replaced by a shot noise.