Hi

My trusty oscilloscope has finally died beyond repair. I have a spare
laptop in my workshop and was thinking about buying a USB
oscilloscope. Is anyone here using one of these things? How do you
rate it? My needs are pretty low spec, dual channel 40MHz will be
fine.

Thanks

On Fri, 25 Sep 2009 12:31:12 +0100, BodgeIt wrote:

My trusty oscilloscope has finally died beyond repair.

If it's Tek or HP, it's probably worth fixing. There are subtle
things that can be seen on an analog scope that a digitized equivalent
sometimes miss.

I have a spare
laptop in my workshop and was thinking about buying a USB
oscilloscope. Is anyone here using one of these things? How do you
rate it? My needs are pretty low spec, dual channel 40MHz will be
fine.

If you're doing just audio, then a sound card based scope might be
sufficient. I mostly use:
http://www.sillanumsoft.org/prod01.htm (Donation suggested)
http://www.zelscope.com ($10)

For fun, I was running an oscilloscope on my Windoze Mobile based cell
phone (Verizon XV6700), but never bothered to register the product:
http://www.virtins.com
http://www.virtins.com/page2.html#Pocket%20Oscilloscope ($25)

The problem with all of these is the limited frequency response (about
20KHz max) and no provisions for measuring DC as in a DVM.

I recently borrowed a CGR-101 USB oscilloscope:
http://www.syscompdesign.com ($197 including shipping and tax)
http://sourceforge.net/projects/oip/
but it doesn't quite meet your requirements (only 20MHz BW). The main
attraction was the VNA features, Labview compatibility, Open Source
(Windoze/Linux/OSx) software. The VNA is limited to 3MHz. I didn't
get to play with it long enough to break much, but it did function
under XP SP3 and OS/X on some fairly marginal hardware. I didn't have
time to try Ubuntu.

A minor problem I ran into was that I have most of my documentation
either online or in PDF format. Since I only have one monitor on the
bench, I was constantly switching back and forth between the schematic
and the scope display. I eventually gave up and just printed the PDF
schematic, which was exactly what I was trying to avoid. Methinks a
USB scope deserves its own computah.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

For casual use, an analog oscilloscope is much more friendly and thus more
useful.

Consider the flea markets/offerings at Hamfests and eBay and perhaps Craig's
list.

Or, as posted, try to fix the one you own.

I don't like digital oscilloscopes (the ones that I can afford).

On Fri, 25 Sep 2009 17:21:13 -0400, "Charles"
wrote:

For casual use, an analog oscilloscope is much more friendly and thus more
useful.

Where can one buy a 20Mhz dual channel analog scope with all the
features of the USB scope for under $200? I'm totally comfortable
with an analog scope, but that's only because I started using scopes
in the 1950's. A Tek 5000 series scope, with a zillion push buttons,
knobs, blinken-lighten, and possible configurations, is not a problem
for me. However, trying to show students, beginners, and engineering
skool graduates, how to operate one, is quite a challenge. They grew
up in the computer age, and are far more familiar with point and
click, and with spinning the knobs and punching the buttons.

Consider the flea markets/offerings at Hamfests and eBay and perhaps Craig's
list.

Yep. This is a repair newsgroup and that's where you get scopes that
have to be repaired.

Or, as posted, try to fix the one you own.

Yep.

I don't like digital oscilloscopes (the ones that I can afford).

What don't you like about them? Does your analog scope do screen
prints? Data logging? Digital readout? Have a built in
signal/sweep/noise generator? Does glitch capture, time rollback,
complex math, storage, waveform comparisons, run on battery, etc? Can
your box be moved or lifted without a scope cart or fork lift? Ad
nauseam. Lots of features in a USB scope that are not found in
commodity analog scopes.

Under $200 is what I consider affordable which is the price of several
commodity USB scopes. However, as speed/bandwidth/resolution
increases, the cost of the A/D box increases dramatically.
Need 12GHz bandwidth? It's only $10,000.
http://www.picotech.com/picoscope9200.html

Marginally related drive: When I inherited some money when my father
died, the first thing I bought with the cash were scope probes.
There's a moral here, but I'll pretend not to see it.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

BodgeIt wrote:

Hi

My trusty oscilloscope has finally died beyond repair. I have a spare
laptop in my workshop and was thinking about buying a USB
oscilloscope. Is anyone here using one of these things? How do you
rate it? My needs are pretty low spec, dual channel 40MHz will be
fine.

Thanks


For something as lo-tech as that you might consider to make one
yourself. A neat little project built around a moderate speed a to d
'verter, maybe go up to 100, or 200, M Samples/sec and then save to a
reg. When you acquire, say, 256 (or however many, maybe from 64 to 1024)
Samples then send them to the pc as one "trace sweep".

Use the printer port, a com port, a usb, or even a firewire for the
transfer (and control), all are pretty much single chip implements.

Write some visual basic or c code for acq and display.
Neato. And you build up all these great skills too.

I would bet you could even find a complete schematic for this online.

DA
p/s Later on, add a d to a and a 4-bytewide storage reg and you have the
basis of a waveform synthesizer on board also. wowie zowie!

"BodgeIt" wrote in message
...
Hi

My trusty oscilloscope has finally died beyond repair. I have a spare
laptop in my workshop and was thinking about buying a USB
oscilloscope. Is anyone here using one of these things? How do you
rate it? My needs are pretty low spec, dual channel 40MHz will be
fine.

Thanks

A few months back, Elektor magazine did an issue dedicated to to virtual
test equipment, and they did detailed reviews of a large number of USB
'scopes, as I recall. Everything is archived on their website, and all the
articles are available for download for a small fee. Might be worth you
searching the issue on their website, and taking a look at the article if
you can find it.

Arfa