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| Rohde & Schwarz Oscilloscopes - Questions/Comments? Let me know! |
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| fonograph:
No,I dont need the answers fast,take your time,just please give me the answers. |
| Rich@RohdeScopesUSA:
--- Quote from: fonograph on October 10, 2017, 03:46:38 pm ---1. What type of filter does RTE use in its hardware anti aliasing front end? Is it butterworth or gaussian? 2. What order is the anti aliasing hardware filter? Is it 4 order? 8 order?? 3. What is the atenuation at nyquist frequency? 4. What filter type is the so called decimator hi res mode? 5. What filter type is the optional 16 bit hi res mode? They say its different from the non-option one,but I cant tell what type is either of them.Hi res is usualy boxcar/rectangular window or gaussian,I want to know what type are both hi res modes. 6. What filter type is the 200Mhz and 20Mhz hardware filter? 7. What order is the 200Mhz and 20Mhz hardware filter? 8. What type is the software bandwidth filter? I mean the filter that exist to block the user from using full bandwidth until he pays for upgrade license. 9. What order is the software bandwidth filter? 10. Does it use any kind of DSP correcting filters? For example phase correcting allpass filters or any kind of phase,group delay or frequency filter on top of any of the filters I already mentioned in previous questions? I have experience that when I unload avalanche of questions on someone,they are unlikely to answer them all or answer at all.I am considering buying RTE,I absolutely need every single of these questions properly and truthfully answered so I know what is the combined phase and group delay response at every particular software bandwidth and hi res setting resuling from all the filters in the scope. --- End quote --- Hi fonograph - sorry it took a bit of time, but here are answers to your questions - please let me know if you need more details. -Rich *************************************** 1. What type of filter does RTE use in its hardware anti aliasing front end? Is it butterworth or gaussian? R&S: See 2. 2. What order is the anti aliasing hardware filter? Is it 4 order? 8 order?? R&S: The anti-alias filter is a 2nd order Bessel filter. (Bessel filter is that type of linear filter with a maximally flat group/phase delay). Up to 1 GHz the phase is almost perfectly linear (Deviation from linear phase +/-1 degree). Up to 1.5 GHz it's within +/-7 degrees. 3. What is the atenuation at nyquist frequency? R&S: The attenuation at nyquist is -20dB 4. What filter type is the so called decimator hi res mode? R&S: See 5. 5. What filter type is the optional 16 bit hi res mode? They say its different from the non-option one,but I cant tell what type is either of them.Hi res is usualy boxcar/rectangular window or gaussian,I want to know what type are both hi res modes. R&S: The HD mode you refer to is now standard on the RTE1000. Different filter types are used depending on the bandwidth of the filters: For high bandwidths, a moving average filter is used. For lower bandwidths, FIR filtering is realized with symmetrical filter coefficients. The roll-off for the FIR filter is Gaussian. 6. What filter type is the 200Mhz and 20Mhz hardware filter? R&S: 2nd order Bessel filter. (Bessel filter is that type of linear filter with a maximally flat group/phase delay).. 7. What order is the 200Mhz and 20Mhz hardware filter? R&S: 2nd order Bessel filter. (Bessel filter is that type of linear filter with a maximally flat group/phase delay). 8. What type is the software bandwidth filter? I mean the filter that exist to block the user from using full bandwidth until he pays for upgrade license. R&S: See 9 9. What order is the software bandwidth filter? R&S: This filter is also an FIR filter. The roll-off depends on the bandwidth of the instrument. 10. Does it use any kind of DSP correcting filters? For example phase correcting allpass filters or any kind of phase,group delay or frequency filter on top of any of the filters I already mentioned in previous questions? R&S: The RTE has some symmetrical linear-phase correction FIR filter for some slight equalization of the magnitude of the frequency response. *************************************** |
| fonograph:
Wow! Thanks Rich! I was thinking you probably wont answer everything,but you did! I would like if you could provide same answers but for RTO,both the old and new one.You dont to repeat everything,just mention those questions whose answer is different from the one you gave me now for RTE. Also,I want to know what are all other differences between the new and old RTO.The newer have bigger screen and different front pannel and knobs,but what else is differet? I think the FFT runs faster on the new one? edit: I would like to separate this further into 4 categories total.The new and old RTO and 10GS/s and 20GS/s models.I have read that old RTO 10 GS/s had gaussian anti aliasing hardware filter,and the 20 GS/s had butterworth aka maximaly flat filter.The new one 20 GS/s now goes up to 6 GHz instead of 4 GHz for old one,so I am not sure what changed,I suspect the filter changed for steeper one or you started using fir filter compensation to make it flat close to nyquist. |
| Rich@RohdeScopesUSA:
--- Quote from: fonograph on October 17, 2017, 03:50:47 pm ---Wow! Thanks Rich! I was thinking you probably wont answer everything,but you did! I would like if you could provide same answers but for RTO,both the old and new one.You dont to repeat everything,just mention those questions whose answer is different from the one you gave me now for RTE. Also,I want to know what are all other differences between the new and old RTO.The newer have bigger screen and different front pannel and knobs,but what else is differet? I think the FFT runs faster on the new one? edit: I would like to separate this further into 4 categories total.The new and old RTO and 10GS/s and 20GS/s models.I have read that old RTO 10 GS/s had gaussian anti aliasing hardware filter,and the 20 GS/s had butterworth aka maximaly flat filter.The new one 20 GS/s now goes up to 6 GHz instead of 4 GHz for old one,so I am not sure what changed,I suspect the filter changed for steeper one or you started using fir filter compensation to make it flat close to nyquist. --- End quote --- Hi fonograph, I'll get the details and come back to you (I'm assuming you don't care about the obvious things like the RTO2000 supports up to 2GSa of memory versus the RTO1000 - you are mainly looking at frontend and filtering differences - is that correct?). -Rich |
| fonograph:
I am interested in other things too,but the thing is,if its in datasheets,then I can look that up myself without bothering you,but these filter details arent in datasheet.So if there is any significant differences then tell me,I am especialy interested on things that arent in datasheet.For example the new RTO might have faster cpu and run faster,or new fft asic or something and if its not mentioned in datasheet I would never know. |
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