[SI-LIST] AW: Re: Frequency components of high speed serial channels
- From: "Havermann, Gert" <Gert.Havermann@xxxxxxxxxxx>
- To: "mrose@xxxxxxxxxxxxxxxxx" <mrose@xxxxxxxxxxxxxxxxx>, "orphanou@xxxxxxxxxxxx" <orphanou@xxxxxxxxxxxx>, "Peter.Pupalaikis@xxxxxxxxxxxxxxxxxx" <Peter.Pupalaikis@xxxxxxxxxxxxxxxxxx>, "joel@xxxxxxxxxx" <joel@xxxxxxxxxx>
- Date: Mon, 3 Mar 2014 09:12:42 +0000
No Silly question at all. Very basic, but not silly.
Taking only the Receiver bandwidth into account is silly as you block high
frequency effects from happening in you simulation and you will be surprised
when they hit you in reality.
The bandwidth of the Transmitter (based on its risetime) is what will be fed
into the real channel. The channel will create non linear frequency dependent
reflections, dispersion and loss, and all that will make the signal look
different at the receiver. Especially xtalk is higher at higher frequencies.
Not taking those frequencies into account when designing the channel means
ignoring its existence and influence, and this is what makes Murphy's Law so
popular.
BR
Gert
----------------------------------------
Absender ist HARTING Electronics GmbH, Marienwerderstraße 3, D-32339 Espelkamp;
Registergericht: Amtsgericht Bad Oeynhausen; Register-Nr.: HRB 8808;
Vertretungsberechtigte Geschäftsführer: Dipl.-Kfm. Edgar-Peter Düning,
Dipl.-Ing. Torsten Ratzmann, Dipl.-Wirtschaftsing. Ralf Martin Klein
-----Ursprüngliche Nachricht-----
Von: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] Im
Auftrag von Rose, Michael
Gesendet: Freitag, 28. Februar 2014 22:43
An: orphanou@xxxxxxxxxxxx; Peter.Pupalaikis@xxxxxxxxxxxxxxxxxx; joel@xxxxxxxxxx
Cc: SI-List
Betreff: [SI-LIST] Re: Frequency components of high speed serial channels
Silly question...
If the RX serdes rolls off noise (may have pole at ~0.7 Nyquist), doesn't that
limit the bandwidth of interest on the channel?
Mike
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Antonis Orphanou
Sent: Thursday, February 27, 2014 1:08 PM
To: Peter.Pupalaikis@xxxxxxxxxxxxxxxxxx; joel@xxxxxxxxxx
Cc: SI-List
Subject: [SI-LIST] Re: Frequency components of high speed serial channels
[cid:image002.jpg@01CF33A3.D5410E10]
Just a visual of the spectral density for a 10Gbps waveform RZ; In theory you
can set a limit of the total power of the signal you want to include and
integrate the spectrum waveform (as shown above) to get the upper frequency
limit. As other members have indicated in their responses, 3~4x the Nyquist at
the rise times we all use should be a good starting point....if your specs are
super tight, use more bandwidth to resolve your waveform...
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Peter.Pupalaikis@xxxxxxxxxxxxxxxxxx
Sent: Wednesday, February 26, 2014 8:25 PM
To: joel@xxxxxxxxxx
Cc: SI-List
Subject: [SI-LIST] Re: Frequency components of high speed serial channels
Hi Joel:
My rule of thumb:
If the rise time is 30% of the UI or slower, look out to 2x the bitrate,
otherwise 3x.
I would not use fractions as the fundamental and harmonics you are referring
to are for a clock. The data signal forms "lobes" with nulls at multiples of
the bitrate.
Pete
Sent from my iPhone
>On Feb 26, 2014, at 6:45 PM, "Joel Brown"
><joel@xxxxxxxxxx<mailto:joel@xxxxxxxxxx>> wrote:
>
>When designing high speed serial channels such as PCIe Gen2 5 GBPS and SATA
>III 6 GBPS what frequency components are of interest? Do you only consider
>the fundamental (2.5 and 3.0 GHZ) or does the third harmonic also need to
>be present for good signal integrity? Most the parts I look at have have a
>few db loss at the fundamental but significant loss at the third harmonic.
>Thanks - Joel
>
>
>------------------------------------------------------------------
>To unsubscribe from si-list:
>si-list-request@xxxxxxxxxxxxx<mailto: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[1<//www.freelists.org/webpage/si-list%5b1>]
>
>For help:
>si-list-request@xxxxxxxxxxxxx<mailto:si-list-request@xxxxxxxxxxxxx> with
>'help' in the Subject field
>
>
>List forum is accessible at:
>
> http://tech.groups.yahoo.com/group/si-list[2<http://tech.groups.yahoo.com/group/si-list%5b2>]
>
>List archives are viewable at:
>//www.freelists.org/archives/si-list[3<//www.freelists.org/archives/si-list%5b3>]
>
>Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu[4<http://www.qsl.net/wb6tpu%5b4>]
>
>
--- Links ---
1 //www.freelists.org/webpage/si-list
2 http://tech.groups.yahoo.com/group/si-list
3 //www.freelists.org/archives/si-list
4 http://www.qsl.net/wb6tpu
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx<mailto: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<mailto:si-list-request@xxxxxxxxxxxxx> with 'help'
in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
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 forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
_______________________________________________________________________
This e-mail and any files transmitted with it are proprietary and intended
solely for the use of the individual or entity to whom they are addressed. If
you have reason to believe that you have received this e-mail in error, please
notify the sender and destroy this email and any attached files. Please note
that any views or opinions presented in this e-mail are solely those of the
author and do not necessarily represent those of the Curtiss-Wright Corporation
or any of its subsidiaries. Documents attached hereto may contain technology
subject to government export regulations. Recipient is solely responsible for
ensuring that any re-export, transfer or disclosure of this information is in
accordance with applicable government export regulations. The recipient should
check this e-mail and any attachments for the presence of viruses.
Curtiss-Wright Corporation and its subsidiaries accept no liability for any
damage caused by any virus transmitted by this e-mail.
------------------------------------------------------------------
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 forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
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 forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
- » [SI-LIST] AW: Re: Frequency components of high speed serial channels - Havermann, Gert
