I have a SDG2042x liberated to a SDG2122x.
There is a bug regarding the phase between the two channels:
Using a sine wave on both channels @ 120MHz @4Vpp there is a difference between the phase of around 12deg or 3.8ns as shown on my scope (Bandwidth 200MHz).
i used two cables with exact the same length to my scope.
Please spend some time in the Utility menu and learn how to phase lock channels etc.
I think you've got the skew calculation backwards (reverse to be CH 1-2), so the real skew measurement is about 257 ps.
Edit: Also, I'm not sure if I'm reading the Keysight scope screenshot correctly, but should you change the channels in the skew (Delay) measurement to be both rising or both falling edge?
Regardless of the way of calculating, my unlocked SDG2042 has a similar phase deviation between it's outputs as yours (@120 MHz with channel locking on).
I'll have to look into that phase calibration procedure you mentioned too.
I'm not sure what the spec is (or if one exists) for output phase alignment between channels on the AWG...
If I set the phasedev to -12 degegree, the two sine outputs are completely in phase. Note that this is at 120MHz.
When I go down in frequency e.g. to 50MHz, the outputs do not stay lined up. The phase difference is -5 deg @50 MHz.
In other words, phase difference between the two channels is frequency dependant.
Sounds like the phase difference is a fixed time (0.28 ns), which of course translates into varying phase angles at the different frequencies. But the generator's channel coupling menu only lets you specify a phase deviation, not an absolute time difference between the channels. So I see that it is a bit inconvenient to correct the deviation on this level.
how did you calculate that number?
Thanks.
Did you mean?
absolute timing difference at 120MHz : 1/(120MHz) * 12°/360° = 277.8 ps
computes to a phase difference at 50 MHz: (360 * 2.77.8E-12) / (1/50E6) = 5 deg
Same as I have measured.
I think that it can be solved using a firmware update:
either changing a parameter in the hardware DAC (I have to look into this)
or using a (interpolated) lookup table and setting the phase angle according to the requested frequency.
Only with a lookup table as the phase deviation varies with frequency.
[...]
I thought maybe FreqCoup in the Channel Coupling menu might null the channel phase difference but no only Phase Coupling> PhaseMode>Deviation seems to work as required however haven't played with PhaseMode>Ratio as yet....getting late now.
Only with a lookup table as the phase deviation varies with frequency.
[...]
I thought maybe FreqCoup in the Channel Coupling menu might null the channel phase difference but no only Phase Coupling> PhaseMode>Deviation seems to work as required however haven't played with PhaseMode>Ratio as yet....getting late now.
Seems to me that it would need a third phase coupling mode, where you specify the deviation as absolute time rather than degrees of phase. (Assuming that the timing offset indeed stays constant across all frequencies.)
'Channel skew adjustment' you mean
Just purchased a Siglent 2042x. It works quite well and I was able to calibrate it to a GPSDO to well under 1 Hz. at 10 MHz using the service menu. Very impressive AWG for the price.
One thing that is disappointing is the level of fan noise when working near the unit. . Not an annoying whine but just much louder than my Siglent 1202X-E scope. Maybe I have a bad fan or that is just the way it is.
Can anyone else comment on the noise level they have experience especially if you have a 1202X-E to compare it to. Hopefully Tautech will comment since he seems to know a lot about this product..
Thanks Roger
I installed the Noctua NF-A6x25 FLX and it has two working fan settings. I used the lowest one and it works great!
Nailig many thanks.
Can you modulate a sine wave properly?
regarding: SDS1202X-E is the quietest fan cooled Siglent product other than those that use smart fans (PSU's and SDL E-load) and SDG products are ~ 2x (my guess) the noise level of SDS1202X-E.
OK, all is now shoe boxed alike and needs cooling! Shaking fan's is not the best for crystal oscillators, so we have free PN or jitter added. may will not see much of them, while performance may not that state of the art, this means enough for home workers
Having a Siglent SDG2082x, SSA 3000X Plus & DSO 2000x Plus on the table and one will but some beans in the ear so you can accept those noise. While world went into fan modding as noise less at it get's. Even with a SSD HD, noise level is reduced..
Also, having a Rigol PSU DP832... fan noise with all to gather, loader than inside a car
Otherwise Tinnitus will your next friend but all likes it cheap, factory to collect each saved penny