Siglent SDG1032X Frequency Counter Precision

[killingtime]

Hi,

I was looking at a Siglent SDG1032X fot HF use. It has AM &FM modulation types (no SSB sadly) and can be upgraded to 60MHz. It also has a 200MHz frequency counter and a 1mHz resolution.

Excited when I saw the resolution, then I saw the clock ppm on the spec sheet: +/- 25ppm

So that's plus or minus 250Hz at 10MHz /2.5KHz at 100MHz, using a display resolution of 0.001 Hz.

Am I missing something here?

Screenshot of the counter page attached.
Spec:
https://siglentna.com/wp-content/uploads/dlm_uploads/2022/06/SDG1000X_DataSheet_DS0201X_E01I.pdf

I think I saw a tear down of a 1032x and saw pcb space for a tcxo instead of the resonator, but I don't see this as a purchase option on Siglents website.

Anyone done the tcxo mod?

Regards.

[colorado.rob]

The SDG1000X has a 10MHz reference input. That's what I use, along with a GPS-DO, on my SDG2000X when precise frequency measurements are required. Those two together make for a very accurate frequency counter.

[killingtime]

Yes, 100 USD buys a GPS-DO, and no need to open the case of the DDS generator, but you need open sky for the antenna.

Ignoring the last 6 digits of readout just surprised me. I've heard of mfrs. giving you the extra 1 digit for marketing purposes, but 6 ....

A 0.1PPM TCXO would give 1Hz uncertainty at 10M and 10Hz at 100M. A lot cheaper as well, but with loss of warranty.

Surprised they didn't use a more stable source. They must have used 25 PPM for a reason. Even 0.5 PPM oscillators aren't that expensive now. Many UHF transceivers use 1 / 2 PPM to avoid interference.

[Hexley]

You might find this apropos : https://www.eevblog.com/forum/testgear/siglent-sdg1000x-series-clock-adjust/msg4081711/#msg4081711

[JehTeh]

I would agree with others who have mentioned using the external reference clock in + GPSDO. On my bench here I have the 2042X, which for reference is within about 0.3-0.5ppm of my GPSDO over a 30 minute window (A BG7 unit+distributor) which normally acts as the reference clock for it).

I actually use it more often than anything else for stuff like quickly tuning RTCs etc. and it works well. The 2042 obviously has a better internal reference than the 1000 series but I think they are fairly similar so with a good external reference I would hope it will work quite well.

[Roger Need]

I would agree with others who have mentioned using the external reference clock in + GPSDO. On my bench here I have the 2042X, which for reference is within about 0.3-0.5ppm of my GPSDO over a 30 minute window (A BG7 unit+distributor) which normally acts as the reference clock for it).

I actually use it more often than anything else for stuff like quickly tuning RTCs etc. and it works well. The 2042 obviously has a better internal reference than the 1000 series but I think they are fairly similar so with a good external reference I would hope it will work quite well.

The 2000x series has a feature that is not in the 1000x series.  That is the ability to manually "tweak" the internal frequency reference to get it extremely close to a 10 MHz. GPSDO.  You have to go into the service menu and then adjust the DAC control to adjust the internal reference frequency.   I use a two channel scope and put the GPSDO on one channel and the internal reference on the other via the BNC on the back.    After a half hour warmup I then slowly adjust the DAC parameter one step at a time until there is minimal drift between the two on the scope.  The end result is exceptional. 

Roger

[Orange]

Beware when using the external freq. input on both types of the generators. The output signal get a lot of spurious components, especially the 1032 or 1062 with the latest firmware.
The previous version is a bit better in this respect, but far from good either.

The 2042 is also a problem with external freq. There are several remarks about it. Siglent ignores the reported issues.

BTW I had the 2042 running on the latest version and noticed that the font of the parameter is smaller, don't like it ; Why oh Why Siglent ? There was nothing wrong with it.....

Fix the dam PLL lock instead of a non issue with the font !

[mawyatt]

Roger,

This is certainly a great feature of the SDG2000X (also the SDG6000X) that doesn't get mentioned often. We use our best in-house reference (not GPS) to tweak the SDGs frequency, wish Siglent would offer this feature on their DSOs tho??

One thing we've noticed when doing the Time Base adjustments on the SDG2000X vs. SDG6000X when using the 2 channel DSO viewing method is the 6000X has much less "random walk" compared to the 2000X. This should signify a lower relative close-in 1/f phase noise of the 6000X 10MHz Reference oscillator.

Best,

[Roger Need]

BTW I had the 2042 running on the latest version and noticed that the font of the parameter is smaller, don't like it ; Why oh Why Siglent ? There was nothing wrong with it.....

Fix the dam PLL lock instead of a non issue with the font !

The font size was reduced in the latest firmware update.  They added more digits to the frequency setting so you can now set milliHertz.   But rather than reduce the graphics they took the lazy way and reduced the font size.  I asked "tautech" if he could suggest to the factory to fix it but will Siglent listen?

Roger

[dbnut]

Excited when I saw the resolution, then I saw the clock ppm on the spec sheet: +/- 25ppm

So that's plus or minus 250Hz at 10MHz /2.5KHz at 100MHz, using a display resolution of 0.001 Hz.

Hi, hope it's not too late for a follow-up question?
Thinking about getting a 1032X or 62X.
After checking endless manuals and videos, I'm still totally confused with what precision output frequency can be entered, say around 1 MHz and 10 MHz.
Seems like only an owner could tell me that
(and yes, a GPSDO EXT REF would be used)

Thanks
Paul

[tautech]

Excited when I saw the resolution, then I saw the clock ppm on the spec sheet: +/- 25ppm

So that's plus or minus 250Hz at 10MHz /2.5KHz at 100MHz, using a display resolution of 0.001 Hz.

Hi, hope it's not too late for a follow-up question?
Thinking about getting a 1032X or 62X.
After checking endless manuals and videos, I'm still totally confused with what precision output frequency can be entered, say around 1 MHz and 10 MHz.
Seems like only an owner could tell me that
(and yes, a GPSDO EXT REF would be used)

Thanks
Paul

Welcome to the forum.

Quick check with 6022X, the only one out, reveals a max of 8 digit resolution and 7 for single digit multipliers.
eg 10 MHz vs 1 MHz.
Therefore 10 000 000 and 1 000 000 provide for 1 Hz frequency steps in the MHz range from inputs via the front panel UI.
SCPI commands may provide for better...need to check.

[modoran]

Nothing special with the frequency counter:

[dbnut]

Aha many thanks, TauTech!
Glad I asked, probably should be looking elsewhere for 1 mHz steps.

[cncjerry]

I'm playing around with my upgraded Siglent 1032x testing an HP5370B.  I have a Rubidium standard on the 5370B and tried bringing that into the 1032x as well.  I see 2V p2p on the reference signal but it doesn't look like the 1032x is recognizing it as the output frequency is still off by 24hz, same as if I disconnect the standard.  I looked around the menus, can't find any way to turn the external frequency reference on.

Ideas?

Jerry

by the way, the reference BNC on the back is labeled In/Out and there isn't a signal on it except for a 16mv, 25Mhz, peak crappy looking square wave.  Looks like there is an issue with the port maybe?

OK, forget all this, I found the setting under "clock". would have named it "reference" myself!  You can turn the output on, etc

Thanks anyway!

[Ringmodulator]

Jerry,

please be aware, that the current firmware has a bug, so that the SDG output does not properly lock to the ref input for output frequencies above arround 30MHz.
I have written abourt this in the main thread.

I did not check, if that also causes an issue with the frequency counter.

Chris