[SI-LIST] Re: balun theory
- From: Paul Levin <levinpa@xxxxxxxxxxxxx>
- To: atifshamimkhan@xxxxxxxxx
- Date: Fri, 09 Jul 2004 11:22:06 -0700
Dear Atif,
Your attachment was stripped off by the list, but I'll try to
reconstruct your figure with words and then explain to you how
it works.
First, I imagine that the two coils run horizontally, one above
the other. The top left corner is driven. The lower left corner
is grounded. The two right ends have a load resistor between
them.
Now, please consider that you have a transformer between the
two coils. Whatever voltage appears on one will have to show
up on the other. If you draw an equivalent circuit starting
with voltage source, source impedance, one half of the transformer,
the load resistor and the other half of the transformer, you will
see that with the way the dots are on the transformer windings,
the transformer has "disappeared." As always, the source impedance
should match the load impedance. But now look at what the transformer
actually did: It applied a negative voltage to one side of the
load and still had a positive voltage on the other side of the
load. It took an unbalanced signal and made it balanced. In
reverse, i.e., right to left, it would take a balanced signal
and make it unbalanced, hence BALanced-UNbalanced or "balun."
Hope that this helps.
Regards,
Paul
_________________
atifshamim khan wrote:
> Hi all
>
> Following figure is a basic balun structure. I have utilized this to
> feed/test an on-chip dipole on bulk Si, but I still dont know how it works in
> theory.
> There is an unbalanced signal (Zin) at the input and a balanced signal at the
> output(load resistor ZL). Basically one end of the transmission line is
> grounded. At the output (the two ZL terminals) have signal which is equal in
> magnitude but opposite in phase.This means that between the two transmission
> lines a phase reversal has taken place. How is this achieved or in other
> words how can we explain the working of this balun in terms of voltages and
> currents or electric and magnetic fields? My guess is that we are forcing and
> odd mode in the transmission lines? Is that right? what is the difference
> between odd mode and even mode impedances here. Any input in terms of
> explanation or references will be appreciated.
> Thanks
> Atif
>
>
> ---------------------------------
> Do you Yahoo!?
> Read only the mail you want - Yahoo! Mail SpamGuard.
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
> List FAQ wiki page is located at:
> http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>
> List technical documents are available at:
> http://www.si-list.org
>
> List archives are viewable at:
> //www.freelists.org/archives/si-list
> or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
>
>
--
Paul Levin
Senior Principal Engineer
Xyratex Storage Systems
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
