Yes, in my opinion the connectors are MCX and I totally agree with Attila about the 20MHz limit. Nice toy to just take a look at low speed signals, for example GPSDOs 10MHz and PPS, serial lines and so on.
On Thu, Feb 23, 2012 at 9:49 PM, Attila Kinali <att...@kinali.ch> wrote: > On Thu, 23 Feb 2012 20:01:18 -0000 > "Rob Kimberley" <robkimber...@btinternet.com> wrote: > > > I'm looking at Item: 300658066641 on EBay, and wanted to know if anyone > in > > the group had any experience of this product. I know this is way off > topic, > > but as a group it's nice to know what's out there and possibly useful in > our > > mutual hobby. > > It depends what you want to use it for. If you just want to have > something protable that can show you roughly what's going on, > then this might be a good thing. For anything else, especially > measurements, > i wouldnt trust it further than i can throw it. > > It's actually quite nice that they put the schematics online too, > so their claims can be verified. > > First that jumps out is that they are using a AD9288-40 as ADC. > Note the -40 there? It means it's an 40Msps ADC. Ie the maximum > usable BW you can have is 20MHz (actually a bit lower). The analog > circuitry doesn't seem too bright either, but i guess you should be > able to get the 20MHz. I havent checked the exact circuitry so > i cannot say whether the input circuit does filter at 20MHz. But > as they claim to have 72MHz analog bandwidth, i would be very carefull > about aliasing problems > > The input circuitry isn't very impressive either and has an undefined > input capacitance (there is a trimmer there) somwhere between 5pF and 30pF > (plus stray capacitances). I find it a it strange, that they disconnect one > input of the frontend opamp... it might anything from going into saturation > to start bouncing around... > The analog switches are rather on the cheap side, nothing you'd expect > in an DSO, but well.. for that price :-) > > Also notice that the connectors used look like SMB or MCX antenna > connectors. Ie those would not be able to withstand many mating/break > cycles. > > Overall, i'd say a good portable gauge, but not much more. > > For a more indepth analysis i'd have to take the schematics apart > into a readable format... > > Attila Kinali > > -- > Why does it take years to find the answers to > the questions one should have asked long ago? > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.