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Impendence?
April 11, 2008

I'm reading a book about jitter and noise when I ran across the word "impendance."

In the text, impendance is used in characterizing the transfer function of an RC network with regard to crosstalk, beginning with an equation. The book reads:

     V=ZvCm(dVd/dt)

     Where Zv is the impendence of the impacted or victim line and dVd/dt is the time derivative of the driving voltage.

I immediately though that "impendence" should be "impedance." But, I Googled "impendence" and found things like...

 "Teseq Inc., a developer and provider of instrumentation and test systems for EMC emission and immunity, has introduced a new impendence stabilization network that is compatible with the highest speed class of Ethernet cables, Category 6."

 Now I’m not so sure that "impendance" is a typo that should be “impedance.” Have you ever used the word "impendance" as it is used in the book?

 I've never heard of an "iimpendence stabilization network" but I have heard of "impedance stabilization network" Is that a typo too?


Posted by Martin Rowe on April 11, 2008 | Comments (4)


April 14, 2008
In response to: Impendence?
Dan Wagner, Motorola commented:

I propose an actual definition for impendence, which should work equally well for probablity, quantum mechanics, and snide comments during re-org announcement meetings: "Impendence is the probability of a possible upcoming event, coupled with its time offset from t=0 (a.k.a. 'now'). Impendence is a function of probability (IMP approaches 0 as p approaches zero, and approaches infinity as p approaches 1), and is inversely proportional to time offset. As an extension of this concept, an event's Loominance is an event's Impdendence coupled with its Graveness."




April 14, 2008
In response to: Impendence?
Dan Wagner, Motorola commented:

I propose an actual definition for impendence, which should work equally well for probablity, quantum mechanics, and snide comments during re-org announcement meetings: "Impendence is the probability of a possible upcoming event, coupled with its time offset from t=0 (a.k.a. 'now'). Impendence is a function of probability (IMP approaches 0 as p approaches zero, and approaches infinity as p approaches 1), and is inversely proportional to time offset. As an extension of this concept, an event's Loominance is an event's Impdendence coupled with its Graveness."




April 16, 2008
In response to: Impendence?
Hank Walker commented:

It must obviously be impedance. The last two terms are the current into the victim, so the voltage is the impedance times the current.




May 1, 2008
In response to: Impendence?
Radio Randy commented:

Hi Martin, After our phone conversation, I too Googled both impendence and impendance. From the results I received, it was obviously a typo. I was just surprised at the number of Web sites that showed the error. A large number of those sites also had the correctly spelled word, elsewhere within the specified documents which enforces the "typo" theory. If you find further technical evidence to support impendance as the correct term, I'll be happy to see it .





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