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| Siglent SDG1032X sine distortion at 1 kHz ? |
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| JBeale:
I'm curious if anyone with a Siglent SDG1032X has measured the sinewave distortion at 1 kHz. I don't have one myself. On page 7 of the spec sheet at https://siglentna.com/wp-content/uploads/dlm_uploads/2022/06/SDG1000X_DataSheet_DS0201X_E01I.pdf it says the sine distortion spec is -60 dBc from 0-10 MHz, at 0 dBm output. On p.3 there is a plot of 2nd and 3rd harmonic levels that suggests -65 dB at 100 kHz, but it doesn't show lower frequencies. I tried building a fixed 1 kHz Wien-bridge oscillator using a NE5534A opamp with the old-school filament lamp for AGC, and that works OK. The sinewave looks unclipped on my scope (which has only 8 bits of resolution I think) but my example barely reaches -60 dB THD, even after adding a few poles of RC low-pass on the output. Now I suppose the audio-frequency ADC I'm using to measure that with might also be far worse than its spec, or my garden-variety 0.1 uF ceramic caps are somehow nonlinear at that level (??) or something else, but so far I can't prove it. |
| Martin72:
--- Quote ---I'm curious if anyone with a Siglent SDG1032X has measured the sinewave distortion at 1 kHz. --- End quote --- Could do this later on.. This threads reminds me of the kit I´ve bought over a year ago and still haven´t assembled yet. It generates a sinewave of 1khz with a claimed thd of round about appx -150dB, theoretically. |
| Performa01:
I do not have an SDG1032X, but I stumbled across an old measurement of the SAG1021, which should be the same circuitry as the integrated AWG of an SDS2000X Plus. In any case this is the cheapest AWG solution from Siglent, so the SDG1000X should be at least as good. The attached image shows the THD from 10 Hz to 1 MHz at 2 Vpp output into 50 ohms. 0.1% equals -60 dBc. |
| Martin72:
Made FFT measures with both generators I currently got, more in the comparison thread... Here single pics, showing the SDG1062X and 2122X, generating a 1khz sinewave with 2.85Vpp. Martin |
| MrAl:
Just to note, my earlier remarks were not intended to suggest that small LCR meters were not useful at all, just not useful for some applications. For example, someone i know talks about getting a small LCR meter for testing inductors. However, he works mainly on DC to DC converters. What would happen if he bought one would be he would be disappointed that they do not work well with converter applications and inductors because inductors used for most converter circuits have more variable characteristics that required a certain DC bias. What this means is the small LCR meter may be of no use at all to him. For more information take a look at an anisotropic curve for any metal core used for converter circuit inductors and also transformers. The inductance may look like 10uH at 10ma but 100uH at 100ma and 1000uH at 1000ma. Then, as the current increases to 2 amps, the inductance may go down to 50uH, then finally down to some very low value maybe almost a short. What this means is that there is no way you can determine how useful a particular inductor is for a converter circuit using a small LCR meter. As far as capacitance, that's a different story because they dont usually need a large current to test properly. Maybe some of the really big ones though like 100000uf and like that, to test for ESR. We could look at some examples. |
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