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