Products > Test Equipment
Siglent SDS1104X-E In-Depth Review
Performa01:
I have updated my review documents that can be found in the initial posts in this thread.
This includes additional/corrected information on noise, XY mode, differentiate math, various typos and mistakes in the FFT review corrected.
An additional part of the review about segmented memory (history and sequence mode) has been posted there as well.
rigol52:
Great review again, Performa01.
Sine max limit is 25MHz. But this is standardized limit and generation probably don't stop at exactly 25MHz.
Curious what would be practical sine limit regarding sine shape (no matter of possible damped amplitude)?
Could it reach 40 or 50MHz and retain sine shape?
Performa01:
--- Quote from: rigol52 on February 21, 2018, 05:41:19 pm ---Sine max limit is 25MHz. But this is standardized limit and generation probably don't stop at exactly 25MHz.
Curious what would be practical sine limit regarding sine shape (no matter of possible damped amplitude)?
Could it reach 40 or 50MHz and retain sine shape?
--- End quote ---
Well, you were asking for it … now fasten your seat belts.
Of course the SAG1021 can output much higher frequencies at slightly reduced amplitude as has already been demonstrated for the noise “waveform”.
But as I have stated in the review, we don’t get a clean signal anymore above 25MHz.
Here is an example for just 30MHz:
SDS1104X-E_Sine_P10_Play_3MHz_FFT
Yes, the harmonics are even lower at -40dBc, but you should also be able to see the upcoming jitter even in the screenshot. Then there is also that nasty spur emerging at 95MHz with an approx. level of just -25dBc…
You will not be surprised to see how matters get worse if we go even higher in frequency. At 40MHz it looks really bad already:
SDS1104X-E_Sine_P10_Play_4MHz_FFT
This time I did not even try to measure the harmonics, but used the strongest spur at 85MHz instead. It is only 18dB below the carrier and also in the time domain we can see really awful things going on.
You don’t want to know what it looks like at 50MHz output frequency, sure you don’t! ;)
It is only natural, as it is basically the same reconstruction problem as in the scope. But there we have some digital signal processing that can calculate the best possible filter for the data available. For a signal generator on the other hand, we need a real filter, i.e. an analog one. You bet your bottom dollar there is none, otherwise we would not be able to see so little amplitude drop at 1.6 times the maximum sine output frequency. Also look at the noise plot up to 200MHz – barely 6dB amplitude drop at the nyquist frequency of 62.5MHz. Nothing even close to the required brick-wall filter. Consequently, with a 2.5-times oversampling (125MHz to 25MHz) the output looks still reasonable (but not stellar, as the sine distortion tests have shown), but any higher, the lack of a proper reconstruction filter becomes just too obvious.
rigol52:
Informative and helpful.
Thanks for all your efforts with subject.
My need with possible new equipment is at least AWG with 40MHz sine.
So it is better to rethink about Siglent SDG1062X in line with SDS1104X-E.
PS: Sorry for typo with your nickname, Performa01, in my previous post.
rf-loop:
@Performa01
In sequence mode if I understand right you show average max sapeed. (how much time some amount of segments aka "frames". But this is not whole truth about speed. One thing is speed what it can use without missing any trigger.
How to test it. (guaranteed max speed)
It can do using pulse generato and burst.
If scope have max amount of frames example 80000 with some t/div.
Set burst n=80000
Set segments n=80000
Set generator example for 400kHz (0r period 2.5µs)
Set scope for normal trig and sequence mode on.
Start burst.
If scope can capture every pulse it can this speed.
Go to higher speed. And repeat until it can not anymore capture every 80000 segment from one burst.
Go slowly back to slower speed until it start capture full burst. Repeat this enough times, example 10...20... or more. (All t/divs with max segment amount.) If it pass every time without any sigle fail, this is guaranteed maximum speed - minimum trusted trigger period time.
Yes this test take lot of time. I have done it for some previous models including SDS1002X-E. Not for SDS10004X-E
For 2 channel model (note FW) it can find here.
Side text is finnish but in table there is finchinglish.
But also, this guaranteed speed what do not miss any single trig is not far away from max average speed today with these bit more mature FW's. (some early time there was more differences if I remember right in SDS2k (notX)).
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