| Products > Test Equipment |
| Siglent SDS1202X-E or Rigol DS1202Z-E |
| << < (9/9) |
| premek_k:
--- Quote --- What Siglent scope? What model? --- End quote --- Exactly like in the topic, Siglent SDS1202X-E. Brand new. --- Quote ---What was the offset, in numbers? At which V/div? --- End quote --- Ofset usually started on 10mV range and differed every time i made a calibration or even restart a device. In best cases it was about 3 divs on 0.5mV range (about 1.5mV), in worse case the curve was totally off screen (more than 2mV). On higher ranges it came better, up to 10mV range, when it was almost zero. Meaning DC offset, of course. How I wrote, an old Rigol scope I have has no DC offset on any range, I assumed this behaviour here too. --- Quote --- FFT peak on low frequencies..... That is you, not understanding how FFT works. Sorry. Frequency of 0 Hz in FFT is representing any DC component (DC offset) in signal. Including DC offset from signal not being fully symmetrical and scope offset. And if you plot FFT in vertical log scale (dBV, dBuV, dBm) it will be visible. For instance if you feed the scope squarewave that is not symmetrical (say 10% duty cycle) that one will have large DC component. You will see that --- End quote --- Roger that, but how I wrote, no signal was connected in these cases, I had a shorted inputs. In my opinion, it accidentally showed some kind of parazital DC offset of the scope. --- Quote ---Also, I hope you didn't buy old Rigol DS2202 but current model Rigol DS2202A. That is a decent scope. FFT will still be much worse Than Siglent has. --- End quote --- Yes, I choose DS2202A. I know, that FFT isn't great, but in fact, firstly I choose a Siglent hoping to save some money on buying a spectrum analyzer. |
| 2N3055:
--- Quote from: premek_k on January 25, 2022, 11:42:19 am --- --- Quote --- What Siglent scope? What model? --- End quote --- Exactly like in the topic, Siglent SDS1202X-E. Brand new. --- Quote ---What was the offset, in numbers? At which V/div? --- End quote --- Ofset usually started on 10mV range and differed every time i made a calibration or even restart a device. In best cases it was about 3 divs on 0.5mV range (about 1.5mV), in worse case the curve was totally off screen (more than 2mV). On higher ranges it came better, up to 10mV range, when it was almost zero. Meaning DC offset, of course. How I wrote, an old Rigol scope I have has no DC offset on any range, I assumed this behaviour here too. --- Quote --- FFT peak on low frequencies..... That is you, not understanding how FFT works. Sorry. Frequency of 0 Hz in FFT is representing any DC component (DC offset) in signal. Including DC offset from signal not being fully symmetrical and scope offset. And if you plot FFT in vertical log scale (dBV, dBuV, dBm) it will be visible. For instance if you feed the scope squarewave that is not symmetrical (say 10% duty cycle) that one will have large DC component. You will see that --- End quote --- Roger that, but how I wrote, no signal was connected in these cases, I had a shorted inputs. In my opinion, it accidentally showed some kind of parazital DC offset of the scope. --- Quote ---Also, I hope you didn't buy old Rigol DS2202 but current model Rigol DS2202A. That is a decent scope. FFT will still be much worse Than Siglent has. --- End quote --- Yes, I choose DS2202A. I know, that FFT isn't great, but in fact, firstly I choose a Siglent hoping to save some money on buying a spectrum analyzer. --- End quote --- Thank you for the answers. You should have returned that scope for replacement. What you saw was some kind of defect. These scopes don't do that. That weird DC offset would definitely show on FFT as DC component, and with log vertical axis would be very visible. That explains that. As I said, DS2000A are decent little scopes. FFT is not very good, but as long you're fully aware and good with that.... As for FFT on ANY scope replacing full SA, it's not gonna happen soon. SA have vastly better dynamic and frequency range and many specialized functions (line noise markers, for instance and all kinds of specialized measurements) that simply cannot be replaced with just scope with FFT. FFT on a scope can be useful in addition to SA, to cover lower frequencies SA won't cover and to do time/frequency domain correlation.... |
| premek_k:
Thank you, 2N3055, for yours reactions. To close this discussion - I'm almost sure, that my piece was broken. But scope came with calibration certificate, someone made a checks. I consulted this wierd things with local dealer and he assured me, that this behavior is not fault. I simply lost confidence in this brand. Generally I am conservative in this regard, I made exception in this case and it didn't turn out well. I realize, that scope FFT can't replace real SA functionality, I use it mostly only for quick look and I was expecting something more from Siglent, but it didn't offer me even a standard. In fact, I'm afraid Rigol won't disappoint me either... ::) |
| 2N3055:
--- Quote from: premek_k on January 25, 2022, 03:53:22 pm ---Thank you, 2N3055, for yours reactions. To close this discussion - I'm almost sure, that my piece was broken. But scope came with calibration certificate, someone made a checks. I consulted this wierd things with local dealer and he assured me, that this behavior is not fault. I simply lost confidence in this brand. Generally I am conservative in this regard, I made exception in this case and it didn't turn out well. I realize, that scope FFT can't replace real SA functionality, I use it mostly only for quick look and I was expecting something more from Siglent, but it didn't offer me even a standard. In fact, I'm afraid Rigol won't disappoint me either... ::) --- End quote --- If I were you I would loose more confidence in local dealer than manufacturer, if manufacturer didn't get a chance to do the right thing. Scope could have been damaged in transport or whatever... I hope you'll be happy with your choice.. DS2000A are actually scopes one step up from Rigol DS1202Z-E OP mentions. They have 2 GSa/s converter, and go up to 350 MHz, and have 56 Mpts of acquisition memory. Siglent model that goes against it is Siglent SDS2202X-E, and has few more protocols, color grading display and few more differences. |
| dec123ua:
Model RIGOL DS1202Z-E SIGLENT SDS1202X-E Price Euro 339 + VAT Euro 339 + VAT Bandwidth 200MHz 200MHz Channels 2 2 Sampling rate 1GSa/sec 1GSa/sec Memory 24Mpts 14Mpts waveform capture rate 30.000wfs/s 100.000wfs/s Timebase Scale 2ns/div - 50s/div 1ns/div - 100s/div Decoding type Parallel, RS232/UART, I2C, SPI I2C, SPI, UART, RS232, CAN, LIN Display 7" 800x480 7" 800x480 |
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