Author Topic: The Siglent SDG2042X Thread  (Read 205521 times)

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Offline mojoe

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Re: The Siglent SDG2042X Thread
« Reply #950 on: June 12, 2018, 12:09:08 pm »
I needed a square wave at 30 MHz, but the SDG2000X only goes up to 25 MHz. So, I created the attached waveform. Using DDS ARB mode, if I key in 3 MHz, I get 30 MHz. This works up to 120 MHz, but by the time you get to 50 MHz, it looks like a sine wave. Above 50 MHz, the amplitude isn't consistent.

To compare the internal square wave to my x10 square wave, I set channel 1 to the built-in 25 MHz square, and channel 2 to my x10 square with 2.5 keyed in.

The two looked similar, and equally usable. One difference was the phase. The x10 square wave had to be set to -5 degrees to coincide with the internally generated square wave. I checked that my cables were matched, using a BNC-T.

As I change frequency, the phase difference also changes. It seems to be linear. Why is there a phase difference between the built-in square wave, and the one generated by the DDS? Why does it change with frequency?

Also, the attached waveform doesn't work the same when using TrueARB mode. I obviously don't understand TrueARB mode. Can someone enlighten me?

 

Offline LaserTazerPhaser

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Re: The Siglent SDG2042X Thread
« Reply #951 on: June 12, 2018, 04:06:30 pm »
So after reading instructions to modify generator am I correct about the modification procedure to max the hardware utilization (120MHz) that no firmware files are required to download and everything is already on the SDG2042X itself? I would much rather they have included nano over vi.
« Last Edit: June 12, 2018, 04:12:29 pm by LaserTazerPhaser »
 

Offline Gixy

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Re: The Siglent SDG2042X Thread
« Reply #952 on: June 12, 2018, 05:02:00 pm »
Hi Mojoe,
I read somewhere (don't remenber in which Siglent document) that the timing accuracy between the two channels is 400ps. That means that the  phase accuracy is variable depending of the frequency :
phi_acc = 360° x 400ps x freq
In your case for 25MHz, the phase accuracy should be : 360° x 400ps x 25MHz =  3.6°, which is close to the 5° you found.
At 120MHz which is the maximum sine wave frequency of the upgraded SDG2042X, you should get 17°, and I measured 13 to 14°.

 

Offline mojoe

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Re: The Siglent SDG2042X Thread
« Reply #953 on: June 12, 2018, 05:29:50 pm »
Gixy,

Thanks for the info. I'll have to try both channels ouputting the built-in square wave to see if I still have the phase difference.

Edit: I just compared both channels, outputting the built-in square wave at 25 MHz. There is a 5 degree phase difference.
« Last Edit: June 12, 2018, 06:17:35 pm by mojoe »
 

Offline Performa01

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Re: The Siglent SDG2042X Thread
« Reply #954 on: June 12, 2018, 08:09:28 pm »
Gixy,

Thanks for the info. I'll have to try both channels ouputting the built-in square wave to see if I still have the phase difference.

Edit: I just compared both channels, outputting the built-in square wave at 25 MHz. There is a 5 degree phase difference.


Have you enabled channel coupling for phase and made sure the phase difference is set to zero?
 

Online exe

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Re: The Siglent SDG2042X Thread
« Reply #955 on: June 13, 2018, 07:14:48 am »
I needed a square wave at 30 MHz, but the SDG2000X only goes up to 25 MHz. So, I created the attached waveform. Using DDS ARB mode, if I key in 3 MHz, I get 30 MHz. This works up to 120 MHz, but by the time you get to 50 MHz, it looks like a sine wave. Above 50 MHz, the amplitude isn't consistent.

AFAIK they can only do ~8-10ns raise time. So, indeed, it can't do square waves above 25MHz, unfortunately.

Concerning amplitude, I don't remember having any issues. Do you have good coax connections with proper termination?
 

Offline mojoe

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Re: The Siglent SDG2042X Thread
« Reply #956 on: June 13, 2018, 01:24:17 pm »

Have you enabled channel coupling for phase and made sure the phase difference is set to zero?

With channel coupling, the phase difference is greatly diminished, but it is still there. If I need the phases to coincide, I'll just have to remember to adjust it.

Edit: To clarify, the above observation was comparing both channels, outputting the built-in square wave. When comparing the built-in waveform to the ARB DDS x10 waveform, channel coupling set to zero makes no difference. I still have 5 degrees difference.

Now that I know the behavior of the SDG, I can adjust to compensate. Thanks to all for the input.
« Last Edit: June 13, 2018, 01:41:41 pm by mojoe »
 

Offline mojoe

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Re: The Siglent SDG2042X Thread
« Reply #957 on: June 13, 2018, 01:36:02 pm »

AFAIK they can only do ~8-10ns raise time. So, indeed, it can't do square waves above 25MHz, unfortunately.

Concerning amplitude, I don't remember having any issues. Do you have good coax connections with proper termination?

The built-in square wave at 25 MHz has a rise time of about 8 ns. The ARB DDS generated square wave at 25 MHz has a rise time of about 4 ns.

As for amplitute, remember, I'm talking about my ARB DDS x10 waveform. The built-in waveforms don't show any variability.
 

Offline tautech

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Re: The Siglent SDG2042X Thread
« Reply #958 on: June 25, 2018, 08:35:56 am »
Hey guys, can someone have a look at precaud's requirements and advise him if 2042X can do what he needs ?
Seems an unusual use case.  :-//

http://www.eevblog.com/forum/testgear/can-your-arb-generator-do-this/
Avid Rabid Hobbyist & NZ Siglent Distributor
 

Offline Adven

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Re: The Siglent SDG2042X Thread
« Reply #959 on: July 15, 2018, 05:13:04 pm »
Hello, So I know I am new and I know this is an old thread, but I could use some help. I have just purchased a SDG 2042X have installed the firmware "downgrade" entered in password and have successfully copy and pasted commands into telnet, successfully "dd" to delete the required line. then press ESC....  and nothing... just a "donk" sound of the key being rejected and cannot enter "wq" to write quit out of program, my Keyboard is on US, I have tried ESC, CTRL+] and CTRL+C nothing is working to get me to the exit prompt to enter WQ to write quit. cannot get it to work on the PC through putty or through CLI on my MAC and Telnet... I can get into the unit but I cannot finish the update to write quit. Please any help is greatly appreciated. thank you.
 

Online exe

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Re: The Siglent SDG2042X Thread
« Reply #960 on: July 15, 2018, 05:19:37 pm »
try esc, then ":wq" (notice colon)
 

Offline Adven

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Re: The Siglent SDG2042X Thread
« Reply #961 on: July 15, 2018, 05:45:16 pm »
try esc, then ":wq" (notice colon)

cheers, but unfortunately I cannot even type anything, after I delete the line required, I hit esc and nothing. it will not let me type or make changes
 

Online exe

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Re: The Siglent SDG2042X Thread
« Reply #962 on: July 15, 2018, 06:05:25 pm »
Then don't hit esc, just type ":wq". If you show me which instructions you follow I can try to figure what's wrong. Should be something very trivial.
 

Offline janekivi

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Re: The Siglent SDG2042X Thread
« Reply #963 on: July 15, 2018, 06:57:35 pm »
 

Offline Adven

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Re: The Siglent SDG2042X Thread
« Reply #964 on: July 16, 2018, 04:09:01 am »
Again, this can help https://www.cs.colostate.edu/helpdocs/vi.html
thank you for the resource, but non of these commands can "be implemented" as the error message at the bottom left side of putty keeps telling me, I'm ensuring that each line is cleanly copy and pasted from the original post (guide for dummies,see quote below)-thank you for that. then when I go to exit non of the commands that should exit me do.

Then don't hit esc, just type ":wq". If you show me which instructions you follow I can try to figure what's wrong. Should be something very trivial.
thank you, and you are completely right, I am sure it is something overly trivial. that's why I'm so baffled, I must be over looking something; and alas, not even just typing the command ":wq" works still says "not implemented" these are the original directions I'm using:
Guide for Dummies

1. Plug in ethernet cable and turn on unit
2. Press Utility -> Page 1/2 -> Interface -> LAN Setup -> DHCP ON
3. On you computer telnet (Windows use Putty, OS X and Linux can just use telnet on the CLI) to the IP Address that's displayed. (If you need to manually specify the port it's 23)
4. mount -o remount,rw ubi2_0 /usr/bin/siglent/firmdata0
5. cp /usr/bin/siglent/firmdata0/NSP_system_info.xml /usr/bin/siglent/firmdata0/NSP_system_info.xml.orig
6. vi /usr/bin/siglent/firmdata0/NSP_system_info.xml
7. Use the down arrow to navigate to the line which has '<license><bandwidth_update_license>xxxx</bandwidth_update_license></license>'
8. Press dd to delete the line. Press ESC. Type :wq then hit enter (write quit)
9. Turn unit off and on again
 

Offline Adven

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Re: The Siglent SDG2042X Thread
« Reply #965 on: July 16, 2018, 04:17:50 am »
I GOT IT!!!!!! THANK YOU ALL FOR YOUR HELP!!!!!! AMAZING!!! was actually a hardware fault on my keyboard, the shift key was not being registered, swapped keyboards and all is well. you are all amazing thanks for all your help and patience!!! all 120 unlocked and golden!
 
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Offline janekivi

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Re: The Siglent SDG2042X Thread
« Reply #966 on: July 20, 2018, 01:18:03 am »
 As were Dave, I'm too a bit annoyed about too long warning message when you dial
to the some parameter limit. This is seems to be hardcoded to 3 in all functions, I wrote
there 1 in those places. Now this delay is much shorter - like 3 times shorter.
I was taking the same latest SDG2000_eevblog_23R7.ads and after editing the app
it is now there if you like to try.
SDG2000_eevblog_edit_23R7.zip
 
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