Six-port article for MUD

Greetings all!

This October, a six-port paper will be included in the Proceedings of Microwave Update 2011. If you read the old six-port paper, this is a major revision and expansion. 

http://www.delmarnorth.com/microwave/newsletters/sixportmodel.pdf

Next step: building six-ports with the recently received couplers and dividers, at 1.2GHz in order to experiment with local amateur DTV. 

https://plus.google.com/114254220048556407553/posts/MVTkLTbNuXB

I'm hoping that experiments at 1.2GHz will produce enough know-how to make a reliable recipe, and then that recipe can be used at 3 and 5 GHz.

I'll be out of town until September 7th. My three children will be back in school on Monday, and I'll begin to have a lot more time to help out on MEP and related experiments. Summer is a bit more challenging in terms of having uninterrupted time.

This list is intended to support and encourage amateur microwave engineering projects, so please speak up with ideas, comments, critiques, proposals and plans. 

Looking forward to the fall, 

-Michelle W5NYV

Sit vis vobiscum!

Qt4 built, building a GUI for SDRs

After reinstalling Xcode, Qt4 installed from the repository. This is the recommended way to build GUIs for MEP. Thanks to Jacob for highlighting Qt4 and recommending a book.

If you're interested in building the GUI, then install Qt and speak up!  :+)

Tom Rondeau had some very nice things to say about a model-view-controller architecture-for-SDR letter I wrote him and fred harris a couple months back. The response got me thinking about exactly how one would want to partition tasks for an SDR, and how those partitions could improve the user experience and user interface.

Model-view-controller type software writing can be very user (and user-interface) focused. What I'd like to look at is how to best write a GUI for SDR. While the application is MEP, I'm looking for generalizations that will be useful to others.

What do you all think?

-Michelle W5NYV

Numbering Scheme, looking for hybrid couplers and dividers, and MUD?

Hi everyone! 

Here's a document about the numbering scheme in the IQ Gain and Phase Correction Filter. 

I bought the first set of parts for experimenting with six-port structures. Two 90 degree hybrid couplers off eBay. The target application is DVB amateur television. There's a repeater near me for DVB ATV. The frequency of interest for this experiment is 1.2GHz.

If you have any 90 degree hybrid couplers or power dividers for this frequency, and are willing to donate them to the cause, let me know! I'm looking for at least 4 more couplers and 2 dividers (0 degree phase, equal power dividers). 

Does anyone have any plans to attend Microwave Update in Connecticut this year? 

 

-Michelle W5NYV

FPGAs in space

Article from EE Times about FPGAs in a cubesat project.

http://www.eetimes.com/design/military-aerospace-design/4216480/High-performance-FPGAs-take-flight-in-microsatellites?cid=NL_ProgrammableLogic&Ecosystem=programmable-logic

 -Michelle W5NYV

Potestatem obscuri lateris nescis.

VHDL implementation compared to MATLAB model - overall success

Overview of successful results with synthesizeable VHDL implementation.
Comparison with MATLAB results.
-Michelle W5NYV

"What's Up With ARM"

Here's an opinion piece about the current state of Linux development on ARM. I
thought it was interesting, largely agree with the author, and wanted to share
it with you guys.

http://www.linux.com/news/featured-blogs/171-jonathan-corbet/445344-whats-up-with-arm

Having got the beagleboard lab back up and running after the extended tour of
duty doing VHDL, I find that it is very true that getting Linux working on ARM
can be much more "some assembly required" than, say, a desktop. It's well worth
it, considering how powerful the ARM family is.

In order to develop something useful for MEP on ARM, there is quite a bit of
slogging to do through various rough edges. When experimenting with cameras and
video output, nothing ever really "quite worked", and the variety and
duplication mentioned in the article were in full evidence.

The current Angstrom build I'm working with was obtained from the Narcissus
Angstrom image builder. I used this because I simply could not get the demo
build of Angstrom to cleanly update from the package server. This sort of
obstacle can be really frustrating.

Here is the link to generate a build of Angstrom:
http://narcissus.angstrom-distribution.org/

This image boots, but I haven't gotten much farther than launching Firefox.

More soon!
-Michelle W5NYV

updated synthesizeable VHDL block - progress

Here is updated VHDL code for the IQ Gain and Phase Correction filter.

I'm working with an adjusted numbering scheme in signed arithmetic to correct an
overflow problem (thanks to KB5MU, who helped identify). 

This implementation, which is designed to be synthesizeable, is beginning to
function as intended. There is a factor of two error, but the compiled block
outputs I and Q.

With some data visualization, these might prove to be a passed-through I and
phase corrected Q at the output, with a massive gain overcorrection. I'll check
that tomorrow!

 -Michelle W5NYV