__________________________________________________________________

   From: coderman <coderman@gmail.com>
   To: David I. Emery <die@dieconsulting.com>; cpunks
   <cypherpunks@cpunks.org>
   Sent:
   Subject: good clocks (not using GPS) and multi-channel hw [was:
   sidebands of great justice]
   >the hardware available for SDR MIMO development leaves much to be
   desired.
   >  ... the blocks and implementations for OFDM coding in software are
   OK :)
   >USRP N2X0 can do it, other setups require external reference clock
   >with high fidelity.  any recommendations for non-GPS clocks performing
   >at 50-100ppb or better?
   Other than a good ovenized crystal oscillator (OCXO), there is
   something called a "DCXO" (Digitally-Compensated Crystal Oscillator)
   that is probably as good as 50 ppb over a moderate temperature range.
   See, for example, :    [1]
   http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1546247&url=http%
   3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4%2F33000%2F01546247.pdf%3Farnumbe
   r%3D1546247
   [2]http://electronicdesign.com/components/dcxo-combines-stability-low-p
   ower
   Jim Bell

References

   1. http:///
   2. http:///