| ??? 10/12/04 13:58 Read: times Msg Score: +1 +1 Informative |
#79207 - Very hard bread to bite... Responding to: ???'s previous message |
Erik said:
there is so much more than just putting the components together to building a scope. I can guarantee you that the gap from "somewhat useable" to "good" (forget excellent) is enormous. I didn't want to sound too demotivating... he also said:
Design is one thing, know-how is another. Just to mention one thing: when you go for 100 MHZ there are things like transmission line effects on your PCB Oh, how right you are!! A bit more than ten years ago I designed a peak detector containing 'DIAMOND' transistor and GaAs-MESFET, which was able to very precisely capture pulses of less than 1nsec! This peak detector was designed for pre-studies about GaAs-microstrip detectors for ATLAS experiment at CERN, to detect the ultra fast pulses resulting from the hit of a MIP (minimal ionizing particle). Although I thought to be a bit experienced in electronics, it turned out, that GHz electronics was totally new to me. There's nothing you can rely on, capacitors look like inductors, inductors look like capacitors, charge injection is totally dominating behaviour of transistor, etc, etc. Each component becomes an individual object, where the dimensions and the actual position of mounting totally determine performance. Finally you end up with ultra little SMD devices where you need a microscope to 'solder'. And you learn to reduce number of used components to the absolute minimum. For someone who is not experienced in analog electronics it's nearly impossible to design a >100MHz storage scope. Perhaps by a very very long series of trials and errors... Nevertheless, I refuse to say, that it's senseless to proceed in this direction. There's so much to learn and to gain. But be prepared, it's a very hard bread to bite... Kai |
