I'm working on an application where the goal is to amplify a signal which is not known exactly but is estimated frequency is between 100KHz and 20MHz. Similarly there is no record of what may be the amplitude is estimated less than 100nV to be expected to be so small that it is undetectable (pV-fV) but to know you are designing a amplifier near 10GV / V Gain multistage variable based on the LMH6629. The input impedance is less than 50 Ohm.
The output of this amplifier is the entrance to the filtering system with an amplifier LOCK IN.
I appreciate suggestions on how to maintain a level of noise and variable gain acaptable the LMH6629.