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REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol

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Teneyes:

--- Quote from: Mark_O on April 11, 2014, 01:53:56 pm ---Think about what '4 Sample points/Data Bit' implies for acquiring comms-type data in segments, in RecordMode!  Properly adjusted, the duration and size can be quite amazing.  At just 4 samples/bit, that's 7x(!) as long as you originally thought possible.

--- End quote ---
Yes  the recorded frame below of a 270 byte/frame and at 8128 frames  shows that 2,194,560 Bytes of data were recorded.
BUT, I adjusted the speed and block size to maximize the capacity of the DSO.
IRL, with the DSO setting a Fixed sample rate for the Timebase and Memory depth selected there will be limitations.

Note: In my test I found 5 samples/bit better as there was missed start bit errors with just 4 samples

Teneyes:
EDIT:    This Bug is Fixed in Latest Firmware 00.03.00.01.03

Here's an Obscure Bug.   It is an ERROR in the displaying of Decoded RS232 Data. under certain conditions  .

The Basic set-up is:
        RS232 Data Triggering on 'Start bit' for 115.2Kb/s
        RS232 DATA Decoding   for 115.2Kb/s
        DSO set for normal Triggering
        DSO set zoom down to 5us/div in Zoom window
        Memory Depth   at   14kPts  ,  140Kpoints
        Timebase settings of 500us  to 10ms

        Data Block set to 10 Bytes burst of Hex '55'
        ( 2 second repeats not significant)
        data pattern  is START (1), 0101 0101 ,  Stop (0)

Below I show a series of Displays, and the descriptions are:
#1  Mem=140K,500us/div,Display of Decoded Data is positioned after Start Bit,  3 Bytes OK
#2  Mem=140K,500us/div,Display of Decoded Data is positioned after Start Bit,  Position  OK
#3  Mem=140K, 1ms/div ,Display of Decoded Data is positioned after Start Bit,  Position  OK
#4  Mem=140K, 2ms/div ,Display of Decoded Data is positioned after Start Bit,  Position  OK
#5  Mem=140K, 5ms/div ,Display of Decoded Data is positioned after Start Bit,  Position  OK
 
#6  Mem=1.4M,500us/div,Display of Decoded Data is positioned near Start Bit,    Position Shifted
#7  Mem=1.4M, 1ms/div ,Display of Decoded Data is positioned near Start Bit,   Position Shifted
#8  Mem=1.4M, 5ms/div ,Display of Decoded Data is positioned before Start Bit, Position Shifted
#9  Mem=1.4M,10ms/div ,Display of Decoded Data is positioned before Start Bit,Position Shifted

#10 Mem= 14M,10ms/div, Display of Decoded Data is positioned after Start Bit,  Position  OK


The ERROR seems to occur only In Zoom window with a Memory depth of 1.4MB and the shift increases as the Timebase is Longer       
The decoding is correct , it is just the Position on the Display is NOT sync'd to the corresponding waveform
NOTE:  in both firmware  00.02.01.00.03 and   00.03.00.00.00

Teneyes:
EDIT:    This Bug is Fixed in Latest Firmware 00.03.00.01.03
The shifting of Decoded Data at 1.4MPts also occurs when a Data Trigger is used.
Note: the Displaying of the Triggering DATA Byte is positoned at the trigger pointer (orange) is when the Data byte is completely detected , at halfway point of the Last Bit in the Data Byte.  For 1.4MPts in is shifted earlier 1.5 bits
Trigger point = x'55' = Binary '85' ,  disappointed that if display is in Hex that the data trigger is not also in Hex

See Displays:

Teneyes:
EDIT:    This Bug is Fixed in Latest Firmware 00.03.00.01.03
After show the shifting of data Bug in previous post , WIM13 referred me to a Decoding BUG at long timebase settings (>10ms/div).
I did some testing , using 56MPts.

Here are displays showing good decoding of long 3000 Bytes data Blocks at 20ms/div using 115200b/s decoding.
All the Decoding is Perfect from first Byte to Last. 
The series of displays are with varying Bit Patterns:  x55, xFF, xF0, and x00.
And Zoomed in to 5.050us/div  , (one byte)
Check them out.

Teneyes:
EDIT:    This Bug is Fixed in Latest Firmware 00.03.00.01.03
The Big Problem with the Perfect displays in my last Post was that the input was at 112000 b/s NOT 115200

Notice the Delay from the trigger to the end of last byte is 267.85 ms
Perfect for  a data rate of 112000 b/s
Bit Rate(b/s)   Bit Period (ms)   Byte period (ms)   Total Block Period (ms)
  112000            0.008929               0.08929                     267.8571

FOR 57.6Kb/s    56Kb/s  shows perfect decoding

I sure wish Rigol checked their Firmware !!!  (00.03.00.00)
I hope this is NOT crippling of the DS2000 DSO, but I think this is on the DS4000 series also.

I'm not doing so well at the 50ms/div timebase ,

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