input impedance

(redirected from External impedance)

input impedance

[′in‚pu̇t im‚pēd·əns]
(electricity)
The impedance across the input terminals of a four-terminal network when the output terminals are short-circuited.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The frequencies of the ADL5811 and ADL5812 can be easily changed using a three-wire SPI (serial port interface), which allows designers to tune the mixers with no need for external impedance matching components.
The modulator's RF port eliminates the need for external impedance matching components.
The terminal characteristics of the MO-CCCDTA are given by [V.sub.p] = [V.sub.n] = 0, [I.sub.Z1] = [I.sub.[Z.sub.2]] = [I.sub.p] - [I.sub.n], [I.sub.X1+] = [g.sub.m1] [V.sub.Z1], [I.sub.X1-] = -[g.sub.m1] [V.sub.Z1], [I.sub.X2+] = [g.sub.m2][V.sub.[Z.sub.2]], and [I.sub.X2-] = -[g.sub.m2] [V.sub.[Z.sub.2]], where [V.sub.z] = [I.sub.z][Z.sub.z] and [Z.sub.z] is the external impedance connected to the Z terminal of the CDTA [25].
External impedance matching circuits are used for tunning of the antenna.
where [g.sub.m] is the transconductance gain of the CFTA and [Z.sub.z] is an external impedance connected to the z-terminal.

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