46results about "Network simulating negative resistances" patented technology

A notch filter suitable for attenuating certain frequencies of a radio-frequency signal includes an input for receiving the radio-frequency signal and an output for the output of a portion of the radio-frequency signal, first and second capacitive means, at least one inductor and a negative resistance circuit suitable for compensating the resistive losses of said at least one inductor. The inductor and the first and second capacitive means are placed to produce a resonator and the filter comprises a control device suitable for controlling the negative resistance circuit. The input impedance of the filter comprises a pole and a zero, with the pole depending on the second capacitive means and the zero depending on both the first and second capacitive means. The first and second capacitive means are variable and the control device is suitable for controlling the first and second capacitive means.

An improved measurement circuit includes a current transformer and an active feedback circuit operated as a negative resistance that matches the value of the winding resistance of the current transformer. An amplifier in the feedback circuit provides power to drive a secondary current through a sense resistor and the transformer winding resistance, reducing the most significant error source in a current transformer circuit by presenting a negative impedance to the current transformer. Combined with the positive resistance of the transformer's winding, the negative impedance results in a net burden of zero on the current transformer, which eliminates the need for the transformer having to provide power to drive the secondary current. This facilitates the use of smaller transformers while achieving reduced measurement errors. Thus, a single, compact measurement device may be used in a wide range of applications with high measurement performance.

A circuit for synthesising a negative resistance, comprising first and second active devices, the first device having a control terminal connected to a first node, and the second device having a current flow terminal connected to the first node, and the first and second devices interacting with each other such that the circuit synthesises a negative resistance.

A tuning circuit using a negative resistance circuit for compensating an equivalent series resistance component thereof is provided. The negative resistance circuit has simple circuit construction and design and adjustment thereof is easy. The tuning circuit comprises a series resonance circuit and a negative resistance circuit connected to the series resonance circuit in series. In the negative resistance circuit, a first transistor constitutes an inverse amplifier by providing a resistor in an emitter circuit thereof and a second transistor constitutes an emitter follower circuit. A positive feedback circuit is constituted by feeding back an output of the emitter follower circuit to an emitter circuit of the first transistor and a negative feedback circuit is constituted by feeding back an output terminal to a base circuit of the first transistor. Thus a negative resistance is produced between this base input terminal and an earth. In this case, since a desired negative resistance value is obtained by adjusting a feedback quantity of both the feedback circuits, Q of the tuning circuit can be set to a desired value.

A Q enhancement circuit and method. In a most general embodiment, the inventive circuit is adapted for use with a component having a parasitic resistance R₃ and a first resistance R₁ disposed in series with the component and an arrangement for making the resistance a negative resistance. In the illustrative embodiment, first and second inductors constitute the components for which Q enhancement is effected. A resistance R₁ is disposed in series with the first inductor and is equal to the parasitic resistance R_L1 thereof. Likewise, a second resistance R₂ is disposed in series with the second inductor and is equal to the parasitic resistance R_L2 thereof. The Q enhancement circuit further includes a first transistor Q₁ and a second transistor Q₂.

An oscillation element that oscillates an electromagnetic wave includes a negative resistance element and a resonator including a first conductor and a second conductor, in which the negative resistance element and the resonator are arranged on a substrate, the negative resistance element is electrically connected to the first conductor and the second conductor, the first conductor and the second conductor are capacitively coupled to each other, and when a capacitance between the first conductor and the second conductor is set as C, an inductance of the first conductor and the second conductor is set as L₁, a speed of the oscillated electromagnetic wave in vacuum is set as C_C, a relative dielectric constant of the substrate is set as ε_r, and a diagonal line length of the substrate is set as d, a series resonant frequency f₁ of the resonator satisfies f₁=1/{2π√(L₁C)}, and f₁<C_o/[d·{(1+ε_r)/2}].

The invention relates to methods and apparatus that receive an integration result, receive logic states of data bits corresponding to the integration result, and perform a high-speed multiplication operation. Embodiments of the invention selectively multiply the integration result according to the logic states of the corresponding data bits. Advantageously, relatively large integration results corresponding to data bit transitions that do not include a change of logic states, such as logic 0 to logic 0 or logic 1 to logic 1, can be multiplied by zero (0). Relatively smaller integration results corresponding to integrations of data bit transitions including a change in logic states, such as from logic 0 to logic 1 or from logic 1 to logic 0, can be multiplied by one (1) and by negative one (-1).

A system and method are provided for isolating an input without adding significant distortion and without significantly adversely affecting the bandwidth of input circuits. In one embodiment, a single ended signal is substantially cancelled by an arrangement including an input resistance path in parallel with a negative resistance path wherein both paths substantially match in resistance. In another embodiment, a differential signal is substantially cancelled by a pseudo differential arrangement including two independent input resistance paths each in parallel with a corresponding negative resistance path, wherein the resistance paths substantially match the input resistance paths. In yet another embodiment, a differential signal is substantially cancelled by a differential arrangement including two resistance paths wherein a first negative resistance path is coupled between the first differential input and the second differential output and the second negative resistance path is coupled between the second input and the first output. In yet another embodiment, a current controlled current source may provide the negative amplification for the negative resistance path.

A negative resistance circuit having a transistor and a plurality of distributed constant lines respectively connected to the three terminals of the transistor further comprises an inductive element or a capacitive element connected between the output terminal of the negative resistance circuit and the ground potential. The negative resistance is adjusted through the inductance of the inductive element or the capacitance of the capacitive element.

An element which oscillates or detects terahertz waves includes a resonance unit including a differential negative resistance element, a first conductor, a second conductor, and a dielectric body, a bias circuit configured to supply a bias voltage to the differential negative resistance element, and a line configured to connect the resonance unit and the bias circuit to each other. The differential negative resistance element and the dielectric body are disposed between the first and second conductors. The line is a low impedance line in a frequency f_LC of resonance caused by inductance of the line and capacitance of the resonance unit using an absolute value of a differential negative resistance of the differential negative resistance element as a reference.

Systems, apparatuses, and methods for implementing a negative resistance circuit for bandwidth extension are disclosed. Within a feedback path of a differential signal path, capacitors are placed on the inputs and outputs of a fully differential amplifier connecting to the differential signal path. In one embodiment, a circuit includes a fully differential amplifier and four capacitors. A first capacitor is coupled between a first signal path and a non-inverting input terminal of the amplifier and a second capacitor is coupled between the first signal path and a non-inverting output terminal of the amplifier. A third capacitor is coupled between a second signal path and an inverting input terminal of the amplifier and a fourth capacitor is coupled between the second signal path and an inverting output terminal of the amplifier. The first and second signal paths carry a differential signal.