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| The Rigol DS1052E |
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| Mastro Gippo:
--- Quote from: rf-loop on March 19, 2010, 05:20:39 am --- I want ask: What are numbers in Y scale? (My quess (becouse these shown numbers) is that they are scope measured RMS and if they are, please connect this 50ohm terminator and test agen ;) ). Sig gen output is for 50ohm load.) What are oscilloscope settings in this measure. Same settings in whole frequency scale? (scope mV/div, equtime or realtime? x ns/div? normal memory? Sinx/x on/off?) What is signal exactly connection to oscilloscope inputs. (cable type/termination? calibration or some opinion how accurate leveling over used freq range = also if it is R&S it may be fail.) If I or somebody tell data/numbers but not tell how I get data/numbers they are nearly or just as garbage... ;) I ask becouse there is something wrong! there is minimum 3 posibilities: 1. Test configuration is bad? (bad cable/missing or fail termination.) 2. Your oscilloscope is fail. (not my first opinion becouse both channels equal) 3. Signal generator is fail. (leveling defect) If all is ok with test: 1052Emod or 1102E frequency response (flatness) is never as bad as in picture. If picture freq response is true for these scopes they are just as toys or garbace stuffs. (but they are not if they work normally) But in real: Simple, I think test configuration fails ;) --- End quote --- whoah, sorry! Numbers on Y scale are mVpp, for the setup I don't know exactly but I think he just wired it up with a bnc-bnc cable, w/o terminator. I'll ask him later, but it's all my fault for not telling him. About oscilloscope settings, I guess he zoomed up as needed to keep the signal well visible. All the other settings should be the default ones, as I factory reseted it after changing SN. By the way, I remember doing a similar test when I got the scope, and with the 50ohm terminator I got a similar "wavy" curve... Can you post the correct setup so I can repeat the test? I feel bad for my father, as he spent 3 hours taking that data for me.. :-[ |
| rf-loop:
Keep macines on minimum 30 minutes before test and before test run Rigol selfcal and maybe also R&S selfcal. Sign gen (R&S) out (N or BNC)-------50ohm cable -------- (50ohm GOOD terminator!)-BNC Rigol CHx R&S out ~106mVrms example 10, 50 or 100kHz and this R&S Vrms level mean that it is TO 50 ohm load IF this instrument is with 50 ohm output (there are also other impedances dependent model options. Temination and cable need match for this) If you forget termination you see wrong level and may see also bad flatness (cable lenght, input of scope etc play together and SWR make all measurements fail (some points may be just ok but you can not know what) and you see near like double values in voltage (in low frequencies). (as can see your data) (note: I do not know this individual sig gen details so I do not know how is this low freq end and is it trusted level in low freq. So if you want 10MHz as reference point for 0dB vertical... use it and do this initial procedure for leveling with example 10MHz (this case use 2ns/diw also for this) -------- EDIT: (SMB100A: Level uncertainty f = 200 kHz to 3 GHz <0.5 dB) so, I recommend to take 200kHz for vertical 0dB ref point and for this initial settings for this test and in this case 1us/div is better for horizontal) -------- Rigol CH1 (or) CH2 only in use. DC 50mV/div 5us/div (use 2 or 5 ns/div if 10MHz as 0dB vertical reference. This case not directly comparable to normal scope specs) equtime Average 8 center trig, center vertical Check rigol with average in use that it show exactly 6div vertical. (exaxtly 300mVp-p +-2mVp-p) If not, adjust R&S level littlebit so that display in Rigol is 300p-p (106mVrms) It is good practice not use maximum vertical area in scope. This scope have 8div vertical so it is reasonamble to use around 6 div. (of course can use what ever levels but this is example and my practice (maybe coming fron Agilent... oh no...I mean Hewlett-Packard of course and Tektronix... ;) ) After this, do not touch R&S output level. Now tst conf is ok and reference is ok for measure BW and also we have 0dB reference point (10, 50 or 100kHz) Change R&S to 10MHz (and later step up forward) Change Rigol to CH1 (or) CH2 only in use. 50mV/div 2ns/div (of course 5 if 1052 original in test) egualtime Average 4 - 8 make tests with all desired freq points between 10 to >200MHz (no need touch vertical speed). rememember wait enough averaging if average is use! (for randomnoise I recommend averaging becouse this is not analog oscilloscope) 10MHz level is typically now around 1- 3% low compare to refpoint. Of course you can also use different test signal levels. (Vp-p = Vrms * 1,4142 * 2) This give good picture about real BW. (BW maybe littlebit different in 2 main bands in V/div settings. listen relay click...you know these bands. 2-200mV and 500mV - 10V also maybe some small differents in other settings) Also if like testing, same with realtime (but sinx OFF becouse sinx in this rigol IS bad) |
| rf-loop:
I think this question is ok specially in this topic now after all this knowledge. I know this is littlebit paranoid question. But I also think that this IS relevant question and maybe it is also hard question. So hard that maybe we do not want know all (possible) dirty truth. Maybe too hard... Peoples buy Rigol DS1102E from china or other country from supplier who do not buy directly from Rigol factory these equipments. How they can really know that they have genuine Rigol factory made original DS1102E or counterfeit? How many pictures we can find what are take inside PCB's from both models. If original factory made 1102 or 1052, are there differencies or are these seen differencies only revision differences. (specially in PCB just after BNC connector.) I can not believe that this is first time when somebody know how to do this modification? Also inside Rigol there are many peoples..... maybe somebody find good "night job". |
| flolic:
I suppose that only way for check if is it genuine instrument is by serial number? |
| rf-loop:
--- Quote from: flolic on March 19, 2010, 11:42:49 am ---I suppose that only way for check if is it genuine instrument is by serial number? --- End quote --- How? |
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