________________________________ 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, : http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1546247&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4%2F33000%2F01546247.pdf%3Farnumber%3D1546247 http://electronicdesign.com/components/dcxo-combines-stability-low-power Jim Bell