[hpsdr] Low phase noise oscillator question

[Kjell Karlsen]

Hi John.

It seems as all the "gurus" are at holidays so I´ll try to comment your  
question:

The 10 MHz oscillator is used only for phase locking of the 122,88 MHz  
clock. This clock has extremely good phase noise and the 10 MHz reference  
oscillator does not degrade this due to the low cut-off frequency of the  
PLL filter. Using a "better" 10 MHz clock can not improve the phase noise  
of the 122,88 MHz clock, just the frequency accuracy.

In Hermes the 10 MHz reference is 2,5 ppm.  The reference used in Mercury  
(and Penny) is 20 ppm. It can be replaced by the one used in Hermes.

73, Kjell




På Thu, 18 Aug 2011 02:25:21 +0200, skrev John Petrich  
<petrich at u.washington.edu>:

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