HI David:
A PIN diode is great for switching RF frequencies above the diode's
lifetime. But not so good at switching DC coupled signals.
The FET type switches, like the MAX458 are designed for switching DC
coupled signals.
Have Fun,
Brooke Clarke, N6GCE
--
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com
David Kirkby wrote:
Poul-Henning Kamp wrote:
Instead of minicircuits I would be looking for video-cross-bar chips.
Any reason to prefer them over the pin diode or GaAs switches from
Minicircuits? I must admit to having no idea how they would compare here.
Maxim as a bunch:
http://para.maxim-ic.com/compare.asp?Fam=Vid_Mux_Buff&Tree=SwitchMux&HP=SwitchMux.cfm&ln=
A MAX458 8x4 switch would be able to drive two counters which could
measure any two of eight sources against each other.
http://pdfserv.maxim-ic.com/en/ds/MAX458-MAX459.pdf
There is even an eval board which does most of the job already:
http://pdfserv.maxim-ic.com/en/ds/MAX459EVKIT.pdf
As far as I can tell you could drive it from a parallel port
with bit-banging.
One thing to note is that Maxim have a *very* nice policy on samples,
which effectively means for experimental purposes, the chips are free.
Just register on their web site, tick what chips you want (limit of
about 6 or 8, no more than two of the same type) and they courier them
to the next day. If you need more than a couple of one type, pick a
standard and an extended temperature range model, and perhaps a mil spec
one too. Or order some more the next day.
I don't think you can get evaluation boards for nothing, but I have not
actually tried.
In contrast, I've always had to pay for Mincircuits bits, but do happen
to have one of their PIN diode switches sitting around.
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