Yet another person asking for Oscilloscope recommendations

Greets everyone and hope you can bear with me.

I'm a hobbyist, not a pro ee. I mainly am learning to work with microcontrollers and repairing (and someday repurposing) old stuff.

Repairing, I work mainly with some household items but mostly with pro-audio equipment from my SO's home music studio and soon a pro studio.

It is definitively time to get my scope, as I frequently need one to diagnose stuff. Thing is I have many constrains that I'll explain.

First is I can most surely not go for an old analog for very cheap on ebay as it will be shipped to the USA and then re shipped from there, and shipping costs for weight and size both are pretty high, and I could end up paying more than $150 shipping on an old tektronix.

That moves me to hink about digital, plus digital comes with some nice stuff I might be using like freq counting, and etc. Plus they're light and small.

Now another limitation is price. I found some 50 mhz rigol at 320 usd which is really the ceiling of what I can afford.

I've been thinking on alternatives and this is where ill need your feedback..

One is one of those cheap Chinese usb boxes in ebay. The trouble with those is I have experience with those things dropping the support off the edge of the Earth very quickly (I have a top2004 ic programmer which barely works today) plus I would love to be able to use a pc scope with open source software in Linux (one can dream).

The other option is the portable open source dso201, being oss means I could get it to work for a lot longer than a brand less closed one, and plus its portable, and can we say field testing? The two drawbacks are, one the rarer probe connector. And two and most important, that it does 72msps, so almost 8mhz (even when some Chinese digital scope vendors insist 250msps is 100mhz), and I wonder as a hobbyist how quickly id hit that ceiling.

Someone mentioned for example arms being 20mhz (outside the range to measure them), I think for microcontroller work my (simple, cheap, oss) LA should do the work, but I fear finding myself having to scope a chip out of my range.

So what di you think? One thing IS a rule though, I need a scope that works NOW and for a long while. It would be "fun" to get and fix an old or new one but I need a working tool.

Thanks all for lending me an ear and expertise, Lars.

 

[Jamie]

lars.gold@gmail.com wrote:

Greets everyone and hope you can bear with me.

I'm a hobbyist, not a pro ee. I mainly am learning to work with microcontrollers and repairing (and someday repurposing) old stuff.

Repairing, I work mainly with some household items but mostly with pro-audio equipment from my SO's home music studio and soon a pro studio.

It is definitively time to get my scope, as I frequently need one to diagnose stuff. Thing is I have many constrains that I'll explain.

First is I can most surely not go for an old analog for very cheap on ebay as it will be shipped to the USA and then re shipped from there, and shipping costs for weight and size both are pretty high, and I could end up paying more than $150 shipping on an old tektronix.

That moves me to hink about digital, plus digital comes with some nice stuff I might be using like freq counting, and etc. Plus they're light and small.

Now another limitation is price. I found some 50 mhz rigol at 320 usd which is really the ceiling of what I can afford.

I've been thinking on alternatives and this is where ill need your feedback.

One is one of those cheap Chinese usb boxes in ebay. The trouble with those is I have experience with those things dropping the support off the edge of the Earth very quickly (I have a top2004 ic programmer which barely works today) plus I would love to be able to use a pc scope with open source software in Linux (one can dream).

The other option is the portable open source dso201, being oss means I could get it to work for a lot longer than a brand less closed one, and plus its portable, and can we say field testing? The two drawbacks are, one the rarer probe connector. And two and most important, that it does 72msps, so almost 8mhz (even when some Chinese digital scope vendors insist 250msps is 100mhz), and I wonder as a hobbyist how quickly id hit that ceiling.

Someone mentioned for example arms being 20mhz (outside the range to measure them), I think for microcontroller work my (simple, cheap, oss) LA should do the work, but I fear finding myself having to scope a chip out of my range.

So what di you think? One thing IS a rule though, I need a scope that works NOW and for a long while. It would be "fun" to get and fix an old or new one but I need a working tool.

Thanks all for lending me an ear and expertise, Lars.

The sampling spec and input spec's are not exactly the same thing.

Normally you want 4 times sampling, so that 250msps sounds about right
for that scope you're talking about.

In digital it takes at least 2 readings to capture a sine wave how
ever, that will be a very bad results.. The software would actually need
to create the sine wave from 2 points on the screen and it would mostly
be inaccurate from the real one. So, using more points to capture data
is the best thing to do.

At the lower sweep rates, the sampling is much higher than can be
processed for viewing, there just isn't enough pixels to show and thus,
most of them just skip over samples and use only the amount that can be
processed as viewable data however, most of these scopes have fancy
functions in them to make use of those other readings, they do not go
unused. You have glitch mode, averaging mode etc.. which uses all the
other samples to help form the data you do see to give you a more
accurate account of what the samples you didn't see by blending them with
those you do see or, making a sample stand out infront of the others
that could be out of place, like in glitch mode. etc..

If you can get a 100 Mhz scope, most likely will sample 4 times that.
one thing you may want to research on however, some of these scopes
interleave their samples from 2 different channels. In other words, if
you have 2 channels operating at the same time, taking readings, you
may only get half the samples per second on each channel. The over all
samples are still the same but they are being divided. If this bothers
you, then look hard at the spec's to make sure the samples per second
remain the same for both channels operating at the same time on each
channel.

A digital scope is very good due to their abilities to host usb
memory and connect to PC's. I don't think you need to worry a lot about
interfacing to PC's. Just get one that is a stand alone but has the
option of connecting to a PC. Most do, I really don't think you want one
that is PC only, those are ok for LAB use if you are logging some work
that needs scope functionality to diagnose it. It makes it easy to then
move the files else where on the PC>

That's my take on it. I am sure others will tell you something, too.

Jamie