[time-nuts] New WWVB modulation format receivers (NOT)
usenet at teply.info
Sat Feb 22 06:24:20 EST 2014
Am Fri, 21 Feb 2014 11:42:05 -0800 (PST)
schrieb Bob Albert <bob91343 at yahoo.com>:
> Oops yes I goofed, it's 500 MHz. 500 GHz is beyond state of the art
> I would think.
Depends on your circuit development skills. Bipolars with gain at
500GHz are in principle possible, both in III/V-semiconductors (InP
comes to mind, but even GaAs might do the trick), and in SiGe this is
currently under research. But you're right, 500GHz at system level is
extremely difficult, I'm not aware of any reasonable demonstration.
5THz (= Far Infrared) is much easier in that regard...
> So GPS satellites are NIST in miniature it seems. That's a lot of
> payload but now I have to see how to gain access to it.
Well, NIST does more than just time, while GPS essentialy is just that:
a precise clock that is also used to calculate positions.
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