handheld oscilloscope $100, any good?

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subatomic
 
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handheld oscilloscope $100, any good?

Post by subatomic »

what's your opinions on this?

VELLEMAN HPS10 Hand Held Oscilloscope
http://www.omnitronelectronics.net/phps ... tem&id=734

Anyone used this one before?
What's your general opinion about handhelds?
Do they work, can they help (or hinder?) doing serious work for audio circuits.
Is there anything I'm going to hate about this?
I can deal with it only having one input...
I'm not concerned with viewing TTL signals at this point...

I have no basis for comparison for this, so any insight about this would be appreciated. Thanks.


Some Background:
I plan to use it on other DIY projects like x0x (9090, Midibox), and maybe develop my own filters and effects as well (anyone want to make an opensource filterbank with me?).

I've used 100Mhz HP and tectronix scopes before, and I realize this wont compare, but I don't want to pay for a high end scope... plus having it portable (like a multimeter) will be really nice.

This would be an upgrade from my '70's Knight kit-scope (just analog, no measurement or analysis). My hope is that I would like it better because of the built in measurement stuff for volts and frequency.

I also considered getting a frequency counter to go with my current cheap-ass scope.

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subatomic
 
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Post by subatomic »

A friend of mine says this:
Cool! $99!

It samples at up to 10MHZ with analog rates up to 2Mhz, these are kind of low, I have pics that operate at 20 mhz or more in the future. When you have a digital sampling o-scope you will need higher sample rates sooner or later. You need 20mhz analog for b&w tv signals and 100mhz for color, for example.

It's cool though and probably worth the money. You should get it and if I like it I'll get one too ; )
I think this scope may be good for audio, but not too good for digital or like he says, tv repairing... :)
If no one posts by the end of the day, I may end up just getting it...

experimental
 
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Post by experimental »

I would be interested in any feedback as well.. Cant beat 99 for scope.

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subatomic
 
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Post by subatomic »

experimental wrote:I would be interested in any feedback as well.. Cant beat 99 for scope.
I ordered it, fingers crossed. I'll report back when it arrives.

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subatomic
 
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Post by subatomic »

It arrived. It's pretty nice. Only $100
Just keep in mind the 10Mhz limit.
It will be great for audio, but not so great for looking at the faster PICs and processors.

A friend of mine got a 200Mhz tectronics on eBay for $300, of course eBay's a pretty uncertain way to get something so take your chances.
I like the smaller pricetag anyway. Leaves more for DIY projects. :)

djarago
 
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Post by djarago »

10MHz isn't even fast enough for a slow MCU. A 100MHz scope would be ok for a 12MHz PIC for example. Think of it like a filter. If you have a 5MHz square wave for example, but you're looking at it with a 10MHz scope then you're going to have a hard time making out a square wave. It will look more like a sine with 1 harmonic at half amplitude. If a scope is 10MHz, usually that means that 10MHz is the -3db point of the filter. Although if you're dealing with even a 48MHz PIC (like I am doing right now) it's fairly unlikely that you're going to have some i/o signal running anywhere near 48MHz.

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subatomic
 
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Post by subatomic »

djarago wrote:10MHz isn't even fast enough for a slow MCU. A 100Mhz scope would be ok for a 12MHz PIC for example. Think of it like a filter. If you have a 5MHz square wave for example, but you're looking at it with a 10MHz scope then you're going to have a hard time making out a square wave. It will look more like a sine with 1 harmonic at half amplitude. If a scope is 10MHz, usually that means that 10MHz is the -3db point of the filter.
yes, everyone should read about nyquist. :)
The scope would only work for sloooowwwww processors.... which these days probably doesn't exist anymore I suppose? ;)

As I stated above I wasn't buying the scope for digital. Only for analog audio. 10Mhz should cover very well the 20hz to 22khz range... If anyone needs to measure digital, then they'll need to spend more on a scope obviously...
djarago wrote:Although if you're dealing with even a 48MHz PIC (like I am doing right now) it's fairly unlikely that you're going to have some i/o signal running anywhere near 48MHz.
True, that's a good point, so the 10Mhz scope may be usable for certain higher-than-10mhz digital applications, as long as the data line you're measuring is running within the range of the scope (probably under nyquist of the scope, see your scope manual for specifics).

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