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DG4000 - a firmware investigation

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MiataMuc:
wild idea (from someone who has never used a jtag-device other than for reading his DS2000 firmware out.. ): would it be possible to put an older (=hack-compatible) Firmware-Version on the DG4000 by jtag?

Flo

rf-loop:

--- Quote from: Teneyes on January 14, 2015, 06:51:00 am ---
--- Quote from: Sparky on January 13, 2015, 06:08:31 am ---Anyone feel free to leave some comments or post comparisons of frequency sweep from your DG4000 units.
--- End quote ---
Here are sweeps on 3 different coax cables
The sweeps are linear from 10-160Mhz over 60sec.
I have to note which cable is best

Note: DSO was in single sweep with DSO trigger out connected to DG sweep trigger input

--- End quote ---

Cables are different, of course. It can read from cables datasheets.

One question about this interesting thing.

Did you use exactly same cable lenght (and not only physical lenght but with around same travel time lenght because it matter. And images looks like there is signal travel time differencies between cables - and impedance mismatches)?

(this question is because there is not 50ohm source impedance and not 50ohm load impedance
Oscilloscope input is mostly NOT 50 ohm impedance at all. It is more like 50ohm resistance for DC.  There is around 50ohm resistance and then inductive and capasitive reactances series and parralle and because this scope input reflects back something more or less and depending cable lenght it affect more or less with different frequencies..)

Teneyes:

--- Quote from: rf-loop on February 02, 2015, 07:53:49 pm ---Did you use exactly same cable lenght (and not only physical lenght but with around same travel time lenght because it matter. And images looks like there is signal travel time differencies between cables - and impedance mismatches)?

--- End quote ---
@rf-loop, Yes the DG4000 generator was set to 50ohm output  and there was a 50 ohm feed-thru termination on the DS2000. 
Yes 2 of the cables were 3 feet long and 1 was 6 feet long.
After I did the Cable sweep  test,  I did do a timing test  to see how much longer the 6' cable was  in time delay, so I connected the shorter cable on Chan.1 and the longer cable on Chan.2  and feed the Sync output pulse from each of the Gen 2 outputs (50 ohm) . One cable is about 6.4 nS longer. the Gen outputs were 'Frequency Locked'.
 
But as I show in the 2nd Pix the timing  drifts over time ( note clock 3hours, and my stored Ref traces, pink and white)  ,
When I reset the 'Phase Align'  the 2 pulses are aligned at the Gen again. see Pix #3 (5 hours)

That is something to know when locking 2 Channels on the DG4000. Frequency Lock does not Lock the phases also.
 

dpenev:
Hi Gents,

The slope of my DG4062 square wave is about 10ns, and this is what i see spicified in the documentataion 
On your pictures I see quicker slopes (about 2ns).
Have you done some calibration to get this?

Regards
Dimitar

   

Teneyes:

--- Quote from: dpenev on February 03, 2015, 11:18:59 am ---On your pictures I see quicker slopes (about 2ns).
Have you done some calibration to get this?

--- End quote ---
If you are referring to the step changes I just posted, please NOTE that I stated the traces are of the Sync outputs, fast switching pulse, but Fixed at 1.6 V .
Good for you to notice the slope, but did anyone notice the trigger point ;D

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