# [SI-LIST] Re: Amplitude loss ?

• From: steve weir <weirsi@xxxxxxxxxx>
• To: rajneesh shukla <rajneeshs123@xxxxxxxxx>
• Date: Fri, 06 Jan 2012 03:34:05 -0800

```Dielectric loss does not increase the effective impedance of either the
near-end or far-end ports.
Steve.

On 1/6/2012 3:14 AM, rajneesh shukla wrote:
>
> Thanks Steve but question remains unanswered !!
>
> I agree there will be a loss in energy due to dielectric loss but I
> was talking about loss in amplitude of signal (voltage) not loss in
> total energy, Energy loss does not always translates into voltage
> loss, right ? Receiver senses voltage( Potential Energy per unit
> charge) not total energy.
>
> As per basic circuit theory, If I have a driver that has zero o/p
> impedance is driving a 50 Ohm load and now if I connect 100 Ohm
> resistance across this load, Though there is energy loss due to 100
> ohm resistance but still my load will see the same voltage, agree ?
>
No I do not agree.  If you change the port impedance you will change the
amount of energy absorbed and the amount of energy reflected.

> In transmission line, If series loss i.e. conductor loss is zero then
> I don't find the reason of any voltage drop in transmission line coz
> dielectric loss which is shunt loss can only dissipate total energy
> but can't change amplitude(voltage) of signal.
>
No I do not agree.  If such a thing were true then you could heat your
on top of it.
>
> Do you find any discrepancy in this analogy ?
>
Yes:  Conservation of Energy and Ohm's Law.
>
>
> On Fri, Jan 6, 2012 at 2:40 PM, steve weir <weirsi@xxxxxxxxxx
> <mailto:weirsi@xxxxxxxxxx>> wrote:
>
>     Follow the energy.  Achieve enlightenment.  Of the energy that a shunt
>     draws, how much of that energy remains available to the signal?
>
>     Steve.
>     On 1/6/2012 12:54 AM, rajneesh shukla wrote:
>     > Experts,
>     > As we know for perfectly matched line insertion loss is due to
>     ohmic&
>     > dielctric losses and due to these losses we see loss in
>     rise/fall time as
>     > well as loss in amplitude of signal.
>     >
>     > My question is what actually affects amplitude loss, is it ohmic
>     loss or
>     > dielectric loss ? My understanding says, it should be ohmic loss as
>     > it comes in series coz dielectric one is shunt loss. If this
>     analogy is
>     > correct then a channel having very low ohmic loss but significant
>     > dielectric loss will have only changes in rise time but minimal
>     amplitude
>     > loss, right ??
>     >
>     > Rajneesh
>     >
>     >
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>     --
>     Steve Weir
>     IPBLOX, LLC
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--
Steve Weir
IPBLOX, LLC
150 N. Center St. #211
Reno, NV  89501
www.ipblox.com

(866) 675-4630 Toll-free
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