Z0 of a line with unequal wires

[modmix]

This does reduce to the correct formula for R_1=R_2. You just need to use the fact that \cosh^{-1}(2 x^2 - 1) = 2\cosh^{-1}(x)[/itex

<br /> Thanks a lot, jason.<br /> <br /> <blockquote data-attributes="" data-quote="jasonRF" data-source="post: 4474316" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> jasonRF said: </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> I have forgotten what little German I learned in high school. </div> </div> </blockquote>similar to my math skills ,-)<br /> <br /> <blockquote data-attributes="" data-quote="jasonRF" data-source="post: 4474316" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> jasonRF said: </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> That document looks great - are you aware of an english translation? </div> </div> </blockquote>As far as I know, text is part of a <a href="http://www.springer.com/engineering/electronics/book/978-3-540-54714-3?token=gbgen&amp;wt_mc=Google-_-Book%20Search-_-Springer-_-DE" target="_blank" class="link link--external" rel="nofollow ugc noopener">Taschenbuch der Hochfrequenztechnik</a>.<br /> <a href="http://www.springer.com/authors?SGWID=0-111-19-36942-0" target="_blank" class="link link--external" rel="nofollow ugc noopener">Apl. Prof. Dr.-Ing. habil. Harald Dalichau</a> was teaching at http://www.unibw.de/eit5/front-page - seems to be retired, though he still appears under http://www.unibw.de/eit5/institut-en. His fon umber isn&#039;t active any more. Switchboard didn&#039;t know anything about him last week.<br /> <br /> In case g00gle doesn&#039;t give a reasonable translation, pls don&#039;t hestitate to contact me by pm.<br /> <br /> <blockquote data-attributes="" data-quote="jasonRF" data-source="post: 4474316" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> jasonRF said: </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> The formula does assume a dielectric medium of infinite extent, of course, but I thought that was the approximation that the OP was asking for. </div> </div> </blockquote>Yes, I think that will be close enough ,-)<br /> <br /> <blockquote data-attributes="" data-quote="sophiecentaur" data-source="post: 4472578" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> sophiecentaur said: </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> P.S. PF does try to deliver when it can! <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f609.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":wink:" title="Wink :wink:" data-smilie="2"data-shortname=":wink:" /> </div> </div> </blockquote>Good to know that <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f642.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":smile:" title="Smile :smile:" data-smilie="1"data-shortname=":smile:" /><br /> <br /> Ulli

 

[sophiecentaur]

Yes, I think that will be close enough ,-)


Ulli

How accurate do you need it to be? How do you plan to terminate the line? This could prove difficult as the line amplifier will need to be constructed pretty carefully to take advantage of any possible advantage. I must say, I am rather skeptical about the worth of this. Particularly if you don't have some pretty sophisticated test equipment. AB comparison is not a conclusive test unless the rest of the system has been thoroughly vetted and calibrated.
Have you any comments about (are you aware of) the consequences of operating a balanced / unbalanced hybrid system?

 

[modmix]

How accurate do you need it to be?

I do not have a written spec.
+/- 1-2 Ω would be fine, I think...

How do you plan to terminate the line?

Oyaide SLSB BNC Plugs

that after spending $100's on the cables

made me smile...
$100 is for the plugs already...

Be assured that the price tag does not in each and every case correlate with the result achieved.
A borrowed $15.000 cable didn't make it - was clear within minutes ​

But, you are right - plugs is an issue...
Unfortunately, they can not be avoided easily...

This could prove difficult as the line amplifier will need to be constructed pretty carefully to take advantage of any possible advantage.

Si.
using this gear for the time being:

I guess, it's done well within the Funk and within the Mutec.
It's not done well in the DEQX, though.
Reference test gear uses a Metrum Hex Dac instead of the DEQX - should be fine there as well.

I must say, I am rather skeptical about the worth of this.

No objection.
Again - we are talking here _not_ about physics. Not yet, at least...
I still do hope that one happy day I'll be able to see some measurements showing the differences I and other do hear.
Than there might be a day where we even do understand what ist responsible for this - than we might be back here at physics and elctronics etc.

Particularly if you don't have some pretty sophisticated test equipment. AB comparison is not a conclusive test unless the rest of the system has been thoroughly vetted and calibrated.

You say it
Be assured that the equipment used for this and other tests is quite sophisticated - up to now, it has shown each and every change precisely and reproducible.

To tell the full sory: some very good gear was replaced as it didn't show some details reported be other people. The gear has to serve for two puroses (at least): enjoy music and be able to detect subtle differences in one or the other component (eg. cable).​

Again, I repeat: this is not yet physics.
And for sure, you need to have good listening capabilities - if mp3 is fine for you, you might save a lot of money for not needingt the stuff I'm talking about.

Have you any comments about (are you aware of) the consequences of operating a balanced / unbalanced hybrid system?

I'ld never say, one or the other is in each and every case the better option.
In the analog domain, I know very, very musical playing gear using unbalanced interfaces, only.

My amps fall into that group - unshielded RCA lines 3m long play just fine... lucky me.​

And I do know some gear playing better when driven balanced.

Test gear falls into that group with respect to NF.​

Both are more or less at the same level - depends on the rest of the chain...

See eg. Douglas Self on noise in balanced vs. unbalanced interfaces when done electronically.
In case you go for transformers, you gain galvanic isolation (no more (or at least less) ground loops), but you pay for it with a mixture of bandwidth limitation, phase shift, distortion and money (might not be a complete list).

Just today we did compare a balanced AES/EBU with a non-75R SPDIF cable between the Mutec MC-3+ and a Metrum Hex Dac :thumbs: - makes me to further investigate that stuff - thanks to this forum, I'm looking forward...

I do regard digital transmission as the transmission of an analoge signal being digitally interpreted at the receiver side. Clean transmission helps to get a proper interpretation - acutally, it is a prerequisite .

 

[davenn]

Oyaide SLSB BNC Plugs

haha ... the spec's for it are basically non existant, they can't even give an impedance rating for the connector. The show you nothing about it. Being a BNC connector in that shape it is presumably like all other BNC connectors and is designed for coax ...
So how do you think you are going to terminate a twin wire into it without causing a significant impedance bump
and therefore destroying any perceived gain for your transmission line ?

I bet they are charging a fortune for these fabled magical musical connectors

When I look for spec's on hi performance connectors for my RF work, the spec sheet can be several pages of data, performance graphs etc and I can see that I am getting an item that is worth the price being paid!

I do regard digital transmission as the transmission of an analoge signal being digitally interpreted at the receiver side. Clean transmission helps to get a proper interpretation - acutally, it is a prerequisite .

And right there is where you are still failing to understand a digital signal
it is a digitally encoded and transmitted signal it is received as such and decoded
there's nothing analog about it
its a string of 1's and 0's, hi's and lo's


Dave

 

[modmix]

Dave,

From an engineering point of view I'm 100% with you.
Seems as if we do not share the same experience - which doesn't fit to engineer's knowledge.

Do we agree that we don't agree on how to cope with that?

Ulli

there's nothing analog about it
its a string of 1's and 0's, hi's and lo's

That's why you can't use an oscilloscope to what the signal eg for detecting impedance mismatch?
Randomly selected example of hi's and lo's:

 

[Baluncore]

In my humble but expert opinion;

The asymmetric parallel conductor equation demonstrates that a symmetrical line is better than an asymmetrical line. This is being ignored by modmix because it is inconvenient.

The use of an exposed digital signal would generate all sorts of noise and interference to other systems. This is being ignored by modmix because it is inconvenient.

This topic is no longer about physics. Reality is being ignored by modmix because it is inconvenient.

This topic should be closed.

 

[davenn]

In my humble but expert opinion;

The asymmetric parallel conductor equation demonstrates that a symmetrical line is better than an asymmetrical line. This is being ignored by modmix because it is inconvenient.

The use of an exposed digital signal would generate all sorts of noise and interference to other systems. This is being ignored by modmix because it is inconvenient.

This topic is no longer about physics. Reality is being ignored by modmix because it is inconvenient.

This topic should be closed.

totally agree

 

[modmix]

bye.

 

[sophiecentaur]

And right there is where you are still failing to understand a digital signal
it is a digitally encoded and transmitted signal it is received as such and decoded
there's nothing analog about it
its a string of 1's and 0's, hi's and lo's


Dave

I have to disagree with you there Dave.

The signal that is carried on any channel is analogue. It involves variations of actual voltages or currents in time and is subject to all the impairments that a straight analogue signal would be. It carries digital information. How well that signal survives is a totally analogue problem. The analogue signal may or may not be recognisable, at the other end, as a series of zeros and ones on an oscilloscope. but what is necessary is that the demodulator sees enough of them correctly to reconstitute the original information. This is what error detection and correction is all about. Many poorly implemented decoders fail to deal with the effects of jitter, interference, distortion or noise. That can be due to analogue imperfections or to poor error correcting or masking. Well before the signal actually crashes, there can be perceptible effects on the output programme signal. Before coming to any conclusions about which part of a channel is dodgy, it is necessary to examine the demodulated bit stream for errors and to see if those errors have the sort of statistics that the coding system can cope with (e.g. interleaving is used to reduce the effects of scratches on audio CDs)

I could put it even stronger and say that any transmission or recording channel that actually uses easily recognised ones and zeros (a set of boxcars) is poorly engineered and is wasting channel capacity. Either more data could be squeezed in or the signal level could be reduced.
Digital engineering hangs totally on Analogue techniques.