So there seems to be an internal difference between the STANDARD 57600 baud decoding and the USERDEFINED 57600 baud decoding in the DS2072. So I tuned down the userdefined baudrate to approx. 56200 baud and at this baudrate the decoding showed exactely the same incorrect decoding like the STANDARD 57600 baudrate mode.Did you find what the higher limit of the UserDefined Baud rate also failed? 59,000?
To see what the tolerance band is.
Does it look like the program is sampling at 56,000 hz and not 57,600hz?
AS 14,400, 28,800, 57,600.... are called 14K 28K and 56K Baud
Maybe the DSO uses also 14000 (instead of 14400), 28000 (instead of 28800) in standard decoding mode - I dont know and have not tested that baudrates jet.
I´m using the latest FW 00.01.01.00.02!
So it´s not a big deal if you know what´s going on because you always can use the user defined baudrate - BUT SEEMS TO BE A FW BUG!
FFT
Maybe the DSO uses also 14000 (instead of 14400), 28000 (instead of 28800) in standard decoding mode - I dont know and have not tested that baudrates jet.
I´m using the latest FW 00.01.01.00.02!
So it´s not a big deal if you know what´s going on because you always can use the user defined baudrate - BUT SEEMS TO BE A FW BUG!
Thanks, Markus. If you could figure out the full parameters of the bug (e.g. by testing the other rates so that we know the extent), we can add it to the FW bug list - and report it to Rigol.
[]The only one who decodes with the wrong baudrate timing is the 57600 one. This decodes with 56000 baud! [/b][/color]
the workaround for this kind of minor bug is quite easy: If you want to decode a 57600 baud serial string, just use the user defined baudrate and set this one to 57600 and everything is decoded fine!Hi Markus
SET THE RS232 TRIGGERING
wondering a bit about that picture, FFT center is 3kHz (so full span 6kHz) but FFT sample rate 10kSa/s ? That didn't make any sense. Or is that zoomed in and moved to left side?The display was 50Hz/div , span of the display =14 x 50 = 700Hz
therefore the display was from 2.65 - 3.35 KHz
"According to the Shannon Sampling Theorem"
The Rigol 'Center' is Not the Center frequency of the Scanned span as in a Spectrum Analyzer.
For Rigol DSOs (D2000,DS4000,DS6000),
The 'Center Freq.' is that Frequency that is set at the Center of the display.
Here is what My DS2072 shows at the left end of the FFT freq.spectrum , always 0 HZ
see display 2 (Rigol center =0kHz )
therefore the display was from 2.65 - 3.35 KHz
When the center of screen is marked as "center", then on left and right side there are exact the same amount of DIVs. As long the FFT is from one edge of the screen to the opposite edge, the center marking is center of full span, a typical center frequency. When you move the FFT to left or right direction then of course that "center" marking if showing the actual frequency on the center line location, so when you move to max. right it will be 0 (or whatever is set to start freq) and when you move to left the full span freq. So whatever you set as DIV, the center marking (again, when position not changed) is always the center frquency of the span. When you zoom in, still the same situation - as long the FFT has been not moved to right or left direction.
and the center is always a center of the screen, so when zero to full span the center marker is center frequency, and when range x to range y then it it still center frequency (of the specific range). Only when you move it's not center frequency anymore, which is exactly what it should be (but maybe you expecting something unexpected from Rigol? )
What DSO do you Have ? a Tekway??
FFT
wondering a bit about that picture, FFT center is 3kHz (so full span 6kHz) but FFT sample rate 10kSa/s ? That didn't make any sense. Or is that zoomed in and moved to left side?
This seems oddly reminiscent of trying to convince you that Rigol's High-Res mode produces the same results as everyone else.
I encountered a mysterious issue when serial decoding a well known 57600 baud serial datastream. The encoding showed me some wrong characters and so I thought maybe the oscillator of the selfmade sending µcontroller device is out of spec. and I tried the "user selectable" baudrate on the DS2072 and at first I used the same baudrate there too, that's 57600. And - I don't know why - when I switched to the user defined baudrate with exactely the same baudrate (57600) the decoding was perfect ! So there seems to be an internal difference between the STANDARD 57600 baud decoding and the USERDEFINED 57600 baud decoding in the DS2072. Does anybody have any idea or could verify this issue on his Rigol DSO.
It's unfortunate that all of this discussion of the 2000 series scopes is contained in a single 104 page thread.
It's unfortunate that all of this discussion of the 2000 series scopes is contained in a single 104 page thread.
Why? I think this whole thread is quite constructive!
In other news, my 2072 just got past US-->Canada customs last night. I hope it comes soon!
[ if you are a new user, it's so hard to skim through the entire thread.
I wonder if there is an efficient way to process all this info. May be the most informative comments should be flagged somehow by readers to make them easier to find.
It's unfortunate that all of this discussion of the 2000 series scopes is contained in a single 104 page thread.
A wiki is a good solution for this kind of thing.
I don't have time to maintain one, which tends to be everyone's problem with this kind of thing, but if someone wants to step up and manage the content I am willing to host one.