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.
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
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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.
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