🚀 go-pugleaf

Richard Henry wrote:
> On Jun 28, 6:03 pm, John Larkin
> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>> On Sun, 28 Jun 2009 12:45:41 -0700 (PDT), Richard Henry
>>
>>
>>
>> <pomer...@hotmail.com> wrote:
>>> On Jun 24, 7:18 pm, "David L. Jones" <altz...@gmail.com> wrote:
>>>> Check out a rather unusual phenomenon you can see on your
>>>> oscilloscope in my
>>>> latest blog (#14):http://www.alternatezone.com/eevblog/
>>>> See if you can get it to happen on your scope!
>>>> I'll offer a free subscription to my blog for the best screen shot
>>>> posted :->
>>
>>>> Oh, and the probe doesn't have to be shorted either.
>>
>>>> Have fun.
>>>> Dave.
>>>> --
>>>> ================================================
>>>> Check out my Electronics Engineering Video Blog &
>>>> Podcast:http://www.alternatezone.com/eevblog/
>>
>>> His schematic of the scope probe and scope input are oversimplified
>>> to the point of incorrectness. Also, he ignored the low-pass nature
>>> of the oscilloscope input, which might contribute to the clean
>>> "sinusoidal" waveform.
>>
>> Scope vertical amps don't ring.
>
> That was not my point.  The limited low-pass band of the input
> amplifier and sampling circuit will either completely filter out
> higher-frequency components, or will alias them down.  If you are
> seeing a nice sinusoidal waveform on an oscillioscope whose
> fundamental frequency is close to the frequency limit of the scope,
> chck it with a higher-frequency device.

I've seen the same (or similar) result with a higher bandwidth (300MHz) 
scope, so the vertical bandwidth limit has nothing to do with it. The 
TDS-220 is just the one I happened to have available at the time. I filmed 
some comment on this extra stuff but it didn't make the cut.

Dave.

-- 
================================================
Check out my Electronics Engineering Video Blog & Podcast:
http://www.alternatezone.com/eevblog/