I'm not sure if it is just software defined, I'm still looking for that.
Today a Rigol DS2072 test device arrived. I took a deeper look onto the circuit and found some further interesting news.
The parts between the relabeled LMH6518 and the garbled IC are also not assembled, so this is not the answer for the bandwidth limitation. The garbled IC's output directly inputs the ADC, there seems to be nothing in between.
Interesting is, that by wetting the garbled IC with some Isoporopanol I found the marking "21AB" (some Rigol code?) and "6552". It's obvious that if they use a relabled LMH6518 (today a TI product) the garbled IC also is a TI one. Also the package seems to be some TI special, which they call 8WSON. Bingo, there is a fully differential opamp from TI named LMH6552, that matches the package, the pinning and the code fragment "6552".
Also interesting is, that the ADC08DL502 from TI (Low Power, 8-Bit, Dual 500 MSPS A/D Converter) seems to match the 144LQFP pinning of the Rigol labeled one. Is this again an overclocked device?
branadic