Parallax USB scope

[victorf57]

I just went to the parallax site and saw a sale of their USB scope.
AT $99.00 it seeems like a great deal.
it's listed under their daily deal but I think it will go through the weekend?

http://www.parallax.com/Store/Access...me,ProductName

Vic.

[Melanie]

But what kind of signals do you want to look at? It's barely good enough for (poor quality) Audio work!

[victorf57]

Yes it is slow.
But at this point I have nothing, and the price is right .
I'm also looking at this one
http://www.hobbylab.us/default.aspx
The scope seem slower but it does have an analyzer .
Vic

[Melanie]

Why does HP sell an Audio Spectrum Analyser for $20K when for five bucks you can buy the software to turn your Audio Line Input Port on your PC into a Spectrum Analyser?

It all depends on your needs. Even if I was a hobbyist, I would want equipment that could do serious work... because somewhere down the line you never know you might end up with some paying work and your toy-town instruments just won't cut it. If you're playing with PICs, you want to go and be able to sample and display 10MHz logic signals at the very minimum. 200kHz bandwidth is just lame.

[Ioannis]

If you want a digital analyzer look at this: http://www.saleae.com/logic/

I 've got just the right moment and solved a problem that I had for 4-5 years!

It was a glitch that I could not catch it on my Tektronix TDS2012...

Then if you want analog signals, follow what Melanie said and find a decent equipment even refurbrished (It was the AFG3022 that I got this way).

Ioannis

[dhouston]

I concur with Melanie and Ioannis. The Parallax scope does what it does reasonably well but what it does is extremely limited. I keep an old PC running W98SE just so I can continue to use my Protek 220 oscilloscope card which requires an ISA slot. The Protek 220 is no longer available but, when it was, sold for about $100. It's a shame that they have not made a PCI version.

• http://www.gigatest.net/hungchang/protek-220.htm

[Normnet]

USB 3.0 could change the speed of USB scopes.
600 Meg bytes per sec for 3.0 vs 60 Meg bytes for 2.0

It would be interesting to see just how fast a PIC could read and send data
to a PC.

Norm

[dhouston]

In this case, the bus speed is not the limiting factor. You can get much better performance from other USB oscilloscopes but it comes at a higher price. For example

• http://www.bitscope.net/store/?p=list&a=list&i=cat+0

[Normnet]

In simplest terms sample, send to PC, and plot on graph.
I bet a FPGA or fast DSP could handle the sample and send part.

Norm

[falingtrea]

Here is a pretty decent USB scope. Sample rate max is 2 giga sample(repetitive)/200 Mega sample (single shot) with a 60 MHz bandwidth. Also has a 8 bit logic analyzer, and pattern generator, and software FFT capability as well. Only $250.

[Ioannis]

Nice site, but do not get carried away by the Sampling numbers. The actual frequency limit is equally impressive low!

Ioannis

[Normnet]

Ill quote Mike Payson from electronics 101:

One interesting Scope alternative that I've been considering picking
up is the FlashyD from FPGA4Fun.

For about $220, you get what amounts to a two channel 220MHz Color
Digital storage OScope (FlashyD Rev K + Saxo). Not bad really. If
you're willing to sacrifice a channel and some speed (60MHz), you can
get the price down to about $72 (Flashy Rev H + Pluto). Several other
configurations are available between (and above) those price points.

The various options are confusing, but it's all explained if you dig
deep enough on that site (The datasheet is very helpful).

Norm