ADS simulation note

[Jared Harvey]

Hello,

I thought some might find this paid for simulation package
interesting. It's ADS put out by Agilent. It helps show what you get
if you pay for your simulation software. I wish I had a pile of $
kicking around, it sure would be fun to work with. Here's a link that
includes a video showing how it works. It's amazing, simply amazing
what you can simulate these days.

http://www.home.agilent.com/agilent/product.jspx?cc=US&lc=eng&ckey=1297113&nid=-34346.0.00&id=1297113

Best regards.

.. ..-. / -.-- --- ..- / .-. . .- -.. / - .... .. ...
.-.. . - ... / .... .- ...- . / .- / -... . . .-.

Jared Harvey Operator KB1GTT

e-mail ma...@jaredharvey.com
Web page http://jaredharvey.com

[AI2Q]

 

Okay, Jared, I've downloaded the latest QUCS version, and unzipped it, and it has created a variety of directories and subdirs on my disk.

 

According to the README docs, which assume you're fluent in Linux, it says:

 

Qucs needs Qt by Trolltech

http://www.trolltech.com.
So, I am installing QT, which is a huge installation.

 

Now, the QUCS docs refer to a tarball, which I assume is Linux jargon for a Zip file or equivalent.

 

It says to unpack the distribution tarball, and that's where it gets sticky. Are the following commands Windows commands at the Start - Run window?

    $ tar xvzf qucs-<version>.tar.gz               (using GNU tar)
    $ gzip -cd qucs-<version>.tar.gz | tar xvf -   (using another tar)
 
Change into the source directory:

    $ cd qucs-<version>

Configure the source package for your system:

    $ ./configure

Now compile the package:

    $ make

Install Qucs:

    $ make install

It says you must must have root privileges if you want to install the package in the
standard location (/usr/local) or in any location that is only writable
by root. This seems VERY cryptic.

Yoiks!  The QT install is running; I'll let you know how it goes.

 

Vy 73, Alex

[Jared Harvey]

Hello,

Sounds like you using Windows, so use the windows installer. Here's a
link to make it easier to find.

http://sourceforge.net/projects/qucs/files/latest/download?source=files

Seems Sourceforge has changed it's pages around a bit, and it was a
bit less than intuitive. I bet you downloaded the version 0.0.1, which
is now something like 0.0.16. That's a problem with SF.

If you are using Linux, it's probably already available via the
systems package manager, so install with that.

[Jared Harvey]

Hello hamnerds,

With our recent talks about PCB's and board
design, I thought I'd pass along a link to a page
that helps give a gut feel for what happens with
PCB current traces as you start to raise the
frequencies.

http://www.maximintegrated.com/app-notes/index.mvp/id/5450

I particularly like the graphics showing where the
currents flow when over about 1KHz. I knew that
traces had a tendency to follow the PCB trace, I
also knew that giving your traces a slight bend
around corners was also good design practice.
However I hadn't really stopped to consider that
the DC component of the trace would not follow the
trace, and I wasn't exactly sure where the
currents resided under the top trace. I also
didn't really know what happened to the currents
when they hit a 90 degree angle.

Now I know and figured I should share.

[AI2Q]

Wow, what an in-depth tutorial, Jared. Thanks for passing it along.

When building up the DDS (direct digital synthesizer) vfo for my homebrew
STAR transceiver, the G3XJP-recommended PCB layout separated the grounds on
the DDS board into digital ground and analog ground. . All the digital
signals and components were on one side of the cut and the analog signals on
the other, just as explained in this article you sent.

Attached is a photo of my homebrew DDS board, and if you look closely you
can see the separate grounds. The cut actually intersects the DDS chip
footprint. The other photo shows the two grounds temporarily linked by a 39
ohm resistor, which I tacked on for the purpose of ringing out the traces
while DC testing.

Vy 73, AI2Q, Alex

[Thomas Liebert]

Thanks for sharing the interesting article, Jared--very informative.

-t

--
73 de Tom NV1T

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