[SI-LIST] Re: A question about how fast the step pulse we need in measuring impedence
- From: <art_porter@xxxxxxxxxxx>
- To: <dave.instone@xxxxxxxxxx>
- Date: Fri, 1 Aug 2008 09:49:46 -0600
Agreed. The higher resolution can also be very handy for
troubleshooting/diagnostic purposes. It also provides better spatial resolution
for locating anomalies. The beauty of normalization is you get both.
Art Porter
-----Original Message-----
From: David Instone [mailto:dave.instone@xxxxxxxxxx]
Sent: Friday, August 01, 2008 9:39 AM
To: PORTER,ART (A-ColSprings,ex1)
Cc: telegrapher9@xxxxxxxxx; huang.jian2@xxxxxxxxxx; si-list@xxxxxxxxxxxxx
Subject: Re: [SI-LIST] Re: A question about how fast the step pulse we need in
measuring impedence
Unless of course you don't meet the spec, in which case the extra
resolution of the faster pulse can help you decide which of all the
'summed' discontinuities is/are the ones to concentrate on fixing.
Regards
Dave Instone
+44 (0)1235 824963
OXFORD SEMICONDUCTOR LIMITED
25 MILTON PARK
ABINGDON
OXFORDSHIRE
OX14 4SH
Registered in England no 2733820
Registered Address: As above
art_porter@xxxxxxxxxxx wrote:
> TDR normalization is the solution to this problem. See app note
> http://cp.literature.agilent.com/litweb/pdf/5988-2490EN.pdf.
>
> Testing with a "real-world" rise time is always best; no point in worrying or
> wasting precious design time on reflections or perturbations that will never
> exist in your real design due to a slower rise time.
>
> Art Porter
> Agilent Technologies
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
> Behalf Of DAVID CUTHBERT
> Sent: Friday, August 01, 2008 8:23 AM
> To: huang.jian2@xxxxxxxxxx
> Cc: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: A question about how fast the step pulse we need in
> measuring impedence
>
> In the case of FR-4 PCB material the relative dielectric constant decreases
> at approximately 0.1 per decade of frequency. The 70 ps rise time vs. the
> 200 ps risetime will result in the Er being measured approximately 0.05
> lower. If you are measuring a 50 ohm line it may measure as 50.3 ohms.
> Dave Cuthbert
> SI, EMC, Analog, RF, Antennas, Pwr (unemployed)
>
> On Fri, Aug 1, 2008 at 4:50 AM, <huang.jian2@xxxxxxxxxx> wrote:
>
>
>> Must we need to filtering the default step pulse that the impedence
>> analyer generates so that the rise time of the filtered step pulse
>> is matching the real condition in the transmission line? For example, the
>> default rise time of step pulse that that the impedence
>>
>> analyer generates is 70ps, and the real rise time of applicable high speed
>> signal in the tranamission line is 200ps.
>>
>> What if the default step pulse with rise time of 70ps used in measuring
>> iimpedence?
>>
>> Thanks in advance
>>
>>
>>
>>
>> --------------------------------------------------------
>> ZTE Information Security Notice: The information contained in this mail is
>> solely property of the sender's organization. This mail communication is
>> confidential. Recipients named above are obligated to maintain secrecy and
>> are not permitted to disclose the contents of this communication to others.
>> This email and any files transmitted with it are confidential and intended
>> solely for the use of the individual or entity to whom they are addressed.
>> If you have received this email in error please notify the originator of the
>> message. Any views expressed in this message are those of the individual
>> sender.
>> This message has been scanned for viruses and Spam by ZTE Anti-Spam system.
>>
>>
>> ------------------------------------------------------------------
>> 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 technical documents are available at:
>> http://www.si-list.net
>>
>> 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
>>
>>
>>
>>
>
>
> ------------------------------------------------------------------
> 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 technical documents are available at:
> http://www.si-list.net
>
> 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
>
>
>
>
> ------------------------------------------------------------------
> 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 technical documents are available at:
> http://www.si-list.net
>
> 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
>
>
>
>
------------------------------------------------------------------
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 technical documents are available at:
http://www.si-list.net
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:
