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REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol
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Teneyes:
OOOH Boy what a Scan and sample rate (5Sa/s)  here
The Warming up of my DSO with terminated inputs.
about 25 minutes between Pix
Note the gradual drift of the trace to Zero over 35 minutes
marmad:
This is basically what a 100kHz sine wave SHOULD look like at 500ms/div:




This is what the Rigol displays @500ms/div using 200kSa/s:




This is what the Agilent displays @500ms/div using 100kSa/s:




Which is closer to the REAL signal?

"Anti-aliasing" should eliminate aliasing - period. If that means that the DSO needs to 'lock' the sample size while the feature is being used - that's what it should do.
marmad:

--- Quote from: Teneyes on July 10, 2013, 08:21:23 am ---I realize that normally the DSO triggers on a select trigger (condition) and that there is a need to record data before and after the event.  I am finding it an annoyance to have to wait as the DSO records long data before I am able to force a trigger.

When I select , "Single" I want 1 event
When I select , a Long time base  , 1 min/div  ( anything greater than 2 seconds)
When I move trigger point to near left edge of the Display ( showing I wish to see data after the trigger)
and then I press a "Force" trigger, I wish to see data Now
 I think the DSO should start the trace immediately and just show the data immediately at the trigger point and NOT make me wait a long time for the DOS to record a preample.

--- End quote ---

@Teneyes: I played around with the slower time bases to see what I could figure out. It appears as if the Rigol has to capture a minimum of ~512 bytes of pre-trigger data; this is when the trigger point is anywhere off the screen to the left (D >= 7 x time base). This pre-trigger data, of course, is what it analyzes to look for triggering events.

The length of time this takes is linked - as it must be - to the sampling rate. So if my memory depth is set to 14kB, then my sample rate at, for example, 200s/div is only 5Sa/s. So that means it takes the DSO ~102.4 seconds to fill the 512 byte pre-trigger buffer before the 'WAIT' status is displayed. OTOH, if my memory depth is set to 56MB, then my sample rate is 20kSa/s, so it only takes ~.0256 seconds to fill the buffer.

If you want the DSO to respond instantly at slow time base settings for Single shot - move the trigger point >= 7 x divisions left and use a large memory depth.
marmad:

--- Quote from: Teneyes on July 10, 2013, 09:36:43 am --- Nope not for me :
  At 20s/div, 14 Mpts, 50KSa/s ,
After moving trigger point to 5 div left of center (on the screen), "Wait" takes 40 seconds to Arm

--- End quote ---

Dude! It's because you're asking it to show you two divisions BEFORE the trigger: 2 x 20 seconds = 40 seconds. How can it show you that if it doesn't first capture it? Move the trigger point 2 divisions left and it will be almost instantaneous to "Wait".  :D
marmad:

--- Quote from: Teneyes on July 10, 2013, 09:36:43 am ---After moving trigger point to 5 div left of center (on the screen), "Wait" takes 40 seconds to Arm

--- End quote ---

Anything visible on the DSO screen which is left of the trigger point is considered pre-trigger buffer. That buffer is FIFO - and needs to be completely filled at the current time base setting before any triggering can happen.  If the trigger point is >= 7 x time base setting, then the pre-trigger buffer is ~512 bytes. Once it's filled, the DSO is ready to be triggered, since new sample data will just overwrite the buffer.
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