Output impedance

About: Output impedance is a research topic. Over the lifetime, 11185 publications have been published within this topic receiving 134949 citations.

A mixed-mode KHN-biquad using DVCC and grounded passive elements suitable for direct cascading

Abstract: In this paper a mixed-mode (input and output signals can be current or voltage) Kerwin–Huelsman–Newcomb (KHN) biquad with low-high input impedance and high-low output impedance depending on the type of the corresponding signal (current-voltage) is presented. The circuit is constructed using three differential voltage current conveyors (DVCCs), two grounded capacitors and three grounded resistors. The circuit simultaneously provides bandpass (BP), highpass (HP) and lowpass (LP) responses when the output is current and notch, BP and LP responses when the output is voltage. The notch and allpass responses can be obtained by connecting appropriate output currents directly without using additional active elements. Because of the low input and high output impedance of the circuit for current signals and the high input and low output impedance for voltage signals, it can be used in cascade for realizing higher-order filters. SPICE simulation results are given to verify the theoretical analysis. Copyright © 2008 John Wiley & Sons, Ltd.

MOS Cascode current mirror

Abstract: An MOS current mirror is disclosed which comprises only two circuit branches and requires only a single reference current. The input circuit branch includes at least four MOS transistors (40, 42, 44, 46) connected in series and the output circuit branch includes at least two MOS transistors (48, 50) interconnected with selected transistors of the input circuit branch. Mirroring of the input current (I REF ) is accomplished by providing a transistor (46, 50) in each circuit branch with identical operating characteristics (V DS , V GS ). High output impedance is achieved in accordance with the present invention by adjusting the channel constant (Z/L) of another transistor (42) in the input circuit branch to be one-third the value of the channel constant associated with each of the remaining transistors.

rf impedance of superconducting weak links

Abstract: The rf impedance of a superconducting weak link with negligible capacitance is calculated for a variety of operating conditions. It is shown that the impedance is always real between harmonic steps of the I‐V characteristic. The real part of the impedance is negative under certain conditions of bias for small rf signals, thus indicating the region of self‐oscillation of the weak link.

Fast transition RF impedance matching network for plasma reactor ignition

Abstract: An impedance matching network for an RF coupled plasma reactor having RF excitation apparatus receiving RF power through the impedance matching network from an RF generator for producing a plasma in the reactor has at least one capacitor connected to the output of the RF generator and having a capacitance value providing an impedance match to the plasma impedance during a steady state of the plasma, at least a first rapidly tunable capacitor connected in parallel with the one capacitor, the rapidly tunable capacitor being rapidly switchable between a high capacitance value providing a match to the plasma impedance during the onset of plasma ignition and a lesser minimum capacitance value, and a controller for rapidly switching the rapidly tunable capacitor from the high to the lesser capacitance value upon reaching the plasma steady state.

Improved acoustic system for auditory research

Abstract: A closed acoustic system, based on the principles of lumped‐element and transmission‐line acoustics, has been developed for use in acute physiological experiments on small mammals. Through the appropriate utilization of a high‐quality push‐pull electrostatic earspeaker (Stax, SRX), a low‐impedance sound source having a relatively flat frequency response and a bandwidth of over 30 kHz is obtained. The output impedance of the source is increased by means of a lumped acoustic resistance in order to match the characteristic impedance of a uniform delivery line. The characteristic impedance of the delivery line is selected so that acoustic stimuli are propagated from the source to the eardrum without the introduction of substantial amplitude and phase distortion. Sound near the eardrum is coupled to a 12‐in. precision condenser microphone through a high‐impedance uniform probe line that is terminated in its characteristic impedance over the range of higher sound frequencies. When electrical equalization of +6 ...