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AN: Open Instrumentation Project Progress

P

PeterH

Jan 1, 1970
0
The Open Instrumentation Project (OIP) has been formed to support
open-source software and low cost hardware for electronic
instrumentation.
Currently available instruments include an oscilloscope, waveform
generator
and network analyser. Source code is available at sourceforge/oip.
Information on the hardware is available at www.syscompdesign.com.

Recent developments in the project:

- The Mac OS-X port appears to be operational, thanks to a contribution
by
Seneca Cunningham. We hope to have the beta test version up on
Sourceforge
shortly. (If you'd like to push that along, send me email and we'll
move it
up in the queue.) This means that the oscilloscope and waveform
generator
are now available for Windows, Linux and Mac OS-X operating systems.

There are three new papers on the Syscomp web page:

- An illustration of oscilloscope single-shot capture operation,
documenting
contact bounce in an electromechanical relay.

- Notes on BNC adaptors and cables, including a pointer to building
cables
using RG-174U (small diameter coax).

- Instructions on Downloading and Executing code from Sourceforge.
(This is
specific to OIP software, but may be useful for other downloads using
the
Tcl/Tk language.)

The vector network analyser which uses the oscilloscope and waveform
generator plus GPLed software, is described in the September issue of
Circuit Cellar magazine.

The oscilloscope software has the following new features:

- Software Zoom (aka Waveform Browser) captures 32k samples and allows
a zoom
into any portion of that data record

- Vertical Calibration allows the vertical sensitivity to be
calibrated, to
yeild improved accuracy over the raw hardware

- X-Y Plot displays in the foreground while displaying X vs time and Y
vs time
in the background. Allows the display of Lissajous figures.

The waveform generator software now supports 0.1Hz resolution. (The
hardware always supported that resolution, now the software takes
advantage
of that.)

Peter Hiscocks
Syscomp Electronic Design Limited, Toronto
http://www.syscompdesign.com
647-839-0325
 
J

Joerg

Jan 1, 1970
0
Hello Peter,

The Open Instrumentation Project (OIP) has been formed to support
open-source software and low cost hardware for electronic
instrumentation.
Currently available instruments include an oscilloscope, waveform
generator
and network analyser. Source code is available at sourceforge/oip.
Information on the hardware is available at www.syscompdesign.com.

Just an idea: What mankind really needs is a simple spectrum analyzer
for EMC pre-compliance work. Nothing fancy, just something that ranges
from 150kHz to 1GHz and can show the ballpark numbers. IOW where people
can see how good their chances are before they head off to that
expensive lab test. This tool would also be useful when they have come
back from the EMC lab with a black eye and must chase those nasty clocks
that pushed them over the cert limits.

It doesn't have to be much, maybe a glorified scanner without a front
panel but with a USB connection and nifty display software.
 
S

Steve Sousa

Jan 1, 1970
0
Just an idea: What mankind really needs is a simple spectrum analyzer
for EMC pre-compliance work. Nothing fancy, just something that ranges
from 150kHz to 1GHz and can show the ballpark numbers. IOW where
people can see how good their chances are before they head off to that
expensive lab test. This tool would also be useful when they have come
back from the EMC lab with a black eye and must chase those nasty
clocks that pushed them over the cert limits.

It doesn't have to be much, maybe a glorified scanner without a front
panel but with a USB connection and nifty display software.

Wouldn't a bunch of antenas and an anechoic chamber be necessary too?

Best Regards

Steve sousa
 
Joerg said:
Just an idea: What mankind really needs is a simple spectrum analyzer
for EMC pre-compliance work. Nothing fancy, just something that ranges
from 150kHz to 1GHz and can show the ballpark numbers.

Err... isn't this a job for an old grid dip meter? Speaking of which,
why
aren't there any NEW grid dip meters? They're as useful a test tool
for RF as strobe lights are for mechanics, but all the ones I see are
leftovers from 30+ years ago.
 
J

Joerg

Jan 1, 1970
0
Hello Steve,
Wouldn't a bunch of antenas and an anechoic chamber be necessary too?

Not necessarily. When I do field work I mostly won't even have access to
a shielded room. There just isn't any on site. Sometimes I rent an
antenna and other times I just use my EMCO probe kit.

Much of my EMI diagnosis for clients happens after a failed EMC test.
Then I already have a baseline, the plots from the lab. So I know that,
for example, 319MHz was 8dB above the line. Now I'll take the analyzer
and go after that. Trying to find what generates it and where it comes out.

The first thing to do before any changes to the unit is to log my own
baseline. It doesn't matter so much what kind of antenna I use, even if
it was a coat hanger from the dry cleaners. It's important to
meticulously document positions, distances, angles etc. Also other
objects in the room. That's why I take my digital camera if the company
allows it.

After finding the root cause(s) and remedies a subsequent scan should
show a drastic reduction. Not just 10dB, considering the uncontrolled
environment that would too close for comfort, but something well north
of 20dB. What I prefer to hear from clients later after the 2nd EMC run
is something like "they couldn't see 319MHz anymore".
 
J

Joerg

Jan 1, 1970
0
Joerg wrote:




Err... isn't this a job for an old grid dip meter? Speaking of which,
why
aren't there any NEW grid dip meters? They're as useful a test tool
for RF as strobe lights are for mechanics, but all the ones I see are
leftovers from 30+ years ago.

Nah, those are too flimsy for that. You need something where you can
connect a probe or antenna to and where you can narrow the detector BW
to 10kHz or so.

Mine is the Heathkit HD-1250. Still works fine and it's probably the
most "modern" dipper that was made (came as a kit though). My oldest is
a Boonton Megacycle meter. Now that is a true grid dip meter because the
detachable head contains a real mini-tube that has a grid. The Heathkit
contains a FET.

Why no new ones? Look what comes out of universities these days. Most of
those folks can't even solder. With hams there also is a disturbing
trend towards not building anything with their own hands.
 
Joerg said:
Hello Peter,



Just an idea: What mankind really needs is a simple spectrum analyzer
for EMC pre-compliance work. Nothing fancy, just something that ranges
from 150kHz to 1GHz and can show the ballpark numbers. IOW where people
can see how good their chances are before they head off to that
expensive lab test. This tool would also be useful when they have come
back from the EMC lab with a black eye and must chase those nasty clocks
that pushed them over the cert limits.

It doesn't have to be much, maybe a glorified scanner without a front
panel but with a USB connection and nifty display software.


Looks like you've just volunteered to design one!

You've been conspicuously absent from the "favorite drinks" thread, I
must add... :)

Michael
 
J

Joerg

Jan 1, 1970
0
Hello Michael,
Looks like you've just volunteered to design one!

Maybe some day. But I am not a USB expert.

You've been conspicuously absent from the "favorite drinks" thread, I
must add... :)

Kind of busy right now and I guess most has already been said. My favorites:

1. Beer (the heavier, darker ales and stouts)

2. More beer.

3. Schnaps (the stuff my wife makes from gin, sugar and blackberries)
 
Joerg said:
Hello Michael,


Maybe some day. But I am not a USB expert.


Atmel seems to make a series of USB controller chips. I stumbled on
them while I was doing research into what microcontroller to use for a
first project. I guess they're similar to using a MAX232 for the
serial port. (They're supposed to shield you from the messy details of
USB.)

http://www.atmel.com/products/USB/

You'll master it within minutes, I'm sure.

Take care,

Michael
 
M

martin griffith

Jan 1, 1970
0
Hello Peter,



Just an idea: What mankind really needs is a simple spectrum analyzer
for EMC pre-compliance work. Nothing fancy, just something that ranges
from 150kHz to 1GHz and can show the ballpark numbers. IOW where people
can see how good their chances are before they head off to that
expensive lab test. This tool would also be useful when they have come
back from the EMC lab with a black eye and must chase those nasty clocks
that pushed them over the cert limits.

It doesn't have to be much, maybe a glorified scanner without a front
panel but with a USB connection and nifty display software.

Yep, seems like a good idea, Joerg
maybe this
http://users4.ev1.net/~wsprowls/ as a starting point.

Warning engineer designed website, may offend many non engineers


martin
 
J

Joerg

Jan 1, 1970
0
Hello Martin,
Yep, seems like a good idea, Joerg
maybe this
http://users4.ev1.net/~wsprowls/ as a starting point.

That is quite a good approach. Nowadays a USB interface would almost be
a must as most laptops do not offer a parallel port anymore. Also, I'd
probably spend a couple bucks more on the log detector :)

Warning engineer designed website, may offend many non engineers

It's quite good but bogs down older PCs because it is all placed on one
long page. Better to split it up and use hyperlinks.
 
M

martin griffith

Jan 1, 1970
0
Hello Martin,


That is quite a good approach. Nowadays a USB interface would almost be
a must as most laptops do not offer a parallel port anymore. Also, I'd
probably spend a couple bucks more on the log detector :)



It's quite good but bogs down older PCs because it is all placed on one
long page. Better to split it up and use hyperlinks.
Just wondering...

Having a laptop next to a spectrum analyser will corrupt all/many of
it readings, wont it?


martin
 
J

Joerg

Jan 1, 1970
0
Hello Martin,
Just wondering...

Having a laptop next to a spectrum analyser will corrupt all/many of
it readings, wont it?

To some extent, yes. But you'd be surprised how much noise modern and
expensive spectrum analyzers let off. Once I was at a client and nobody
had a clue where a new forest of noise peaks could possbibly be coming
from. There was nothing on the plots from the EMC lab, total silence in
that range. So I got some aluminum foil from the cantina and waved it
here and there. Surprise: When I held it in front of the $20k+
analyzer's LCD screen the noise disappeared.

One can live with problems like that. Furnace filter mesh, fencing
materials, aluminum screen door stock, all that helps as long as you can
see the display through it. One of the first questions when arriving for
an EMI job at a new client is where the next hardware store is located.

USB and power cables would need some #43 ferrite but almost any EMI job
requires to keep a couple of pounds of those at hand anyway.
 
R

Robert Latest

Jan 1, 1970
0
On Wed, 04 Oct 2006 22:29:07 GMT,
in Msg. said:
That is quite a good approach. Nowadays a USB interface would almost be
a must as most laptops do not offer a parallel port anymore.

Wouldn't an FT245R from FTDI be an almost drop-in replacement?

robert
 
from 150kHz to 1GHz and can show the ballpark numbers. IOW where people
That is quite a good approach. Nowadays a USB interface would almost be
a must as most laptops do not offer a parallel port anymore. Also, I'd
probably spend a couple bucks more on the log detector :)

What about an ethernet interface..?

Meaning there is actually something interesting to read and no BS ;)
 
martin griffith said:
On 05 Oct 2006 10:19:58 GMT, in sci.electronics.design
[email protected] wrote:
Sort of, I just think that one long scrolling page is a PITA, this one
is even worse
http://www.redrok.com/main.htm

Reminds me of a person at uni that didn't know how to use an editor so he
wrote all documents in the same file.. until the editor couldn't handle it ;)

Maybe the html author have same problem? =)

Way better..
http://wiki.aydogan.net/index.php/Main_Page
 
D

Donald

Jan 1, 1970
0
Robert said:
Wouldn't an FT245R from FTDI be an almost drop-in replacement?

robert

No

Programming a USB parallel port is not like programming for a hardware
parallel port.

Software that uses a hardware parallel port can not just use a USB port.

A total re-write of the I/O in the PC app would be needed.

donald

PS: If anyone has code available to interface to a USB parallel port,
please share any links or code.
 
J

Joerg

Jan 1, 1970
0
What about an ethernet interface..?

That would be ok but needs setup. Which means extra work. A well
engineered USB device plugs in and the matching software miraculously
shows up ;-)
Meaning there is actually something interesting to read and no BS ;)

True. But a wee bit of skill application in organizing a document would
have been nice.
 
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