🚀 go-pugleaf

"David L. Jones" <altzone@gmail.com> wrote in message 
news:aAM8m.14055$8B7.9612@newsfe20.iad...
> a7yvm109gf5d1@netzero.com wrote:
>> On Jul 19, 7:04 am, "David L. Jones" <altz...@gmail.com> wrote:
>>> As promised, an expos� of an issue with the Rigol DS1052E
>>> oscilloscope in my
>>> latest video blog:http://www.alternatezone.com/eevblog/
>>>
>>> Dave.
>>> --
>>> ---------------------------------------------
>>> Check out my Electronics Engineering Video Blog &
>>> Podcast:http://www.alternatezone.com/eevblog/
>>
>> You corrected the number of PLLs in the FPGA, how do they get the
>> clocks' phases aligned?
>
> Beats me.
> Could be as simple as fixed tuned gate delay inside the FPGA, or could 
> be some more complex system that auto-calibrates perhaps.
>
>> I'm no expert on digital scopes, but I suppose
>> the clock frequency changes depending on the time base?
>
> Only when required when the memory is full.
> On short memory mode (1GS/s, 16KB) a relay clicks in at 100ns/div and 
> it tells you it's doing 1GS/s on 50ns/div to 5ns/div.
> No such click occurs when in long memory mode (500MS/s 1Mpoints), and 
> it stays on 500MS/s up to 100ns/div.
> The relay is thus most likley switching the input signal between 
> either 5 or 10 ADC's depending upon the requirement.
>
>> Do they just drop some ADCs and keep the frequency, thereby 
>> permitting
>> the use of trace delays to get the 100ps delays or what?
>> Are the GS/s figures real time or equivalent time?
>
> 1GS/s real time of course, that's been the selling point of these 
> Rigol scopes for the last 5 years or so.
>
>> I think it is possible Rigol tests the ADCs and bins them in-house. 
>> Do
>> you think they might run the power supply a bit "hotter" to get the
>> parts to work at higher clocks?
>
> I don't think so, likely they have just done exhaustive testing of 
> these parts to ensure the work. Binning each one in house would be 
> possible, but messy.
> Perhaps AD are the ones pulling the swifty and charging a huge premium 
> (almost 3 times) for the exact same part?
>
> Dave.
> -- 

It could have been a purchasing error, that actually works.
Or, the parts marked as 40 don�t meet the specs over temperature for a 
100/80 mhz clock.
Perhaps  NL specs are not met but Rigol can compensate for the error.
I've seen -40c to 85c parts work beyond the rated specs, with some 
additional error.

Cheers