[SI-LIST] GND Separation for Analog & Digital circuits
- From: "Geva" <geva@xxxxxxxxxxx>
- To: <leeritchey@xxxxxxxxxxxxx>, "Zhangkun" <zhang_kun@xxxxxxxxxx>,<maheshwari@xxxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Fri, 20 Feb 2004 21:47:29 -0800
Hello Maheshwari,
To answer your question on separate analog and digital GND for Video and
digital signals;
I had very similar problem of CATV receiver with video at 43 and 5 MHz,
combined with digital signals on same board.
In the PCB layout design we completely separated the 2 grounds and later
on, in the lab, we found out the optimum
locations of connections between the digital GND and the Analog GND, and how
many connections needed, for the best performance.
in order to get the best signal to noise ratio, we used more than one
connections between grounds.
You may come with many theoretical conclusions about one or more connection,
but the test will specified the best answer for you.
Ehood Geva
----- Original Message -----
From: "Lee Ritchey" <leeritchey@xxxxxxxxxxxxx>
To: "Zhangkun" <zhang_kun@xxxxxxxxxx>; <maheshwari@xxxxxxxxxx>;
<si-list@xxxxxxxxxxxxx>
Sent: Friday, February 20, 2004 9:43 AM
Subject: [SI-LIST] Re: Separate GND for Analog & Digital
> Zhangkun,
>
> Thanks for sharing your results. It supports the concept of keeping the
> noise out of the analog section by careful routing of those traces.
>
> Lee
>
>
> > [Original Message]
> > From: Zhangkun <zhang_kun@xxxxxxxxxx>
> > To: <maheshwari@xxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
> > Date: 2/20/2004 9:13:05 AM
> > Subject: [SI-LIST] Re: Separate GND for Analog & Digital
> >
> > Dear Maheshwari
> >
> > We have come cross the simular problem. The critial point is to prevent
> return path of digital signal disturbing the analog signal.
> >
> > In one of our PCB, there is too much digital noise in analog signal. We
> have to repair it. How to seperate the ground seemed to be the most
> important problem. One is to seperate the ground and to connect the
digital
> ground and analog ground at one point. The other is not to seperate the
> ground. In order to make sure that the product is OK, we made two boards,
> seperated and not seperated. In the test, both boards are OK.
> >
> > It has nothing to do with seperating ground or not. Being care of the
> digital return path is the most important. Some CAD tools could do such
> simulation.
> >
> > I hope this will help.
> >
> > Best Regards
> >
> > Zhangkun
> > 2004.2.20
> >
> > ----- Original Message -----
> > From: "Maheshwari.P" <maheshwari@xxxxxxxxxx>
> > To: <si-list@xxxxxxxxxxxxx>
> > Sent: Thursday, February 19, 2004 7:41 PM
> > Subject: [SI-LIST] Separate GND for Analog & Digital
> >
> >
> > > Hi All,
> > >
> > > I am designing boards which contain Audio and Video codecs. I need to
> pass
> > > analog signal to the corresponding decoders without much noise.
> > >
> > > Is it better to have separate analog and digital GND?
> > > or
> > >
> > > Is it better to have a solid GND and have separate analog and digital
> > > sections?
> > >
> > > Which of the either way will give better results in terms of audio and
> video
> > > quality?
> > >
> > > Thanks in advance,
> > > Maheshwari
> > >
> > > ------------------------------------------------------------------
> > > 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.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
> > >
------------------------------------------------------------------
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.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:
