Re: Digital Storage Scopes 'Record Length'


Don Black <donald_black@...>
 

I've just bought a cheap DSO to connect to my computer via USB and am still learning about it. I'll make the following comments and hope someone really familiar with DSOs will correct any wild flights of fancy, It seems the little scope can store hundred(s?) of M Bytes of data.

I assume you mean a digital storage scope, not a sampling scope that needs a repetitive signal. 2500 samples are very few by todays technology, I guess you're talking of an era when memory was scarce and expensive. With a modern digital scope you can store a long stream of data and should find the glitch.

Don Black.

On 17-Aug-13 8:11 PM, egroups@... wrote:
 

Hi D., Henrik, David,

so apparently it looks like that, for instance, examining a short glitch (some ms) in a
very slow signal (seconds) is most likely not possible in a straight forward manner.
Either the anti-aliasing-filter would smooth it out and/or it simply would fall
between two samples.
So the only chance would be a single shot measurement, possibly triggered by this
error event (glitch) and maybe with some sort of pre-recording to get the complete
section of the distortion.
Either way I can't see it at all nor I can determine the exact position of it
in order to track down its cause.
Do Tek scopes provide anything that would be helpful in that way?

Thanks, Michael.

On 15.8.2013, at 17:51 , cheater00 . wrote:

> 2500 kHz is not a whole lot if you think in terms of time.
> However, it's very likely to be able to characterize a single period
> of the wave being sampled. Sampling oscilloscopes only work for
> repeating waveforms anyways, unless you do single-shot mode and accept
> a very heavy bandwidth penalty.

On 15.8.2013, at 18:23 , Henrik Olsson wrote:

> Generally speaking the scope selects a sample rate so that the memory
> will last for the duration of the "sweep". Ie, if you select 1ms/div
> and there's 10 divisions on your screen the memory will have to last
> for 10ms so the scope selects a sample rate of 250k samples per second.

On 15.8.2013, at 18:30 , David wrote:

> Using dimensional analysis:
>
> 250 samples/div divided by 1s/div = 250 samples / 1 second
> total time captured is 1s/div * 10 divisions = 10 seconds
>
> 250 samples/div divided by 1us/div = 250 samples / 1 microsecond
> 250 samples/div divided by 1us/div = 250 million samples per second
> total time captured is 1us/div * 10 divisions = 10 microseconds


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