[time-nuts] How to get 32.768KHz from 10MHz.
bruce.griffiths at xtra.co.nz
Wed Jul 23 19:19:50 EDT 2008
An oscillator can be injection locked to at frequency that is a rational
number (M/N where M, N are integers ) multiplier of the injection frequency.
Thus, in principle, a 32768Hz oscillator can be injection locked
directly to a 10MHz signal (32768Hz = (256/78125)*10MHz) without
requiring any external dividers or multipliers.
In practice this will only be practical with a 32768Hz crystal
oscillator whose frequency determining crystal is tuned sufficiently
closely to 32768Hz.
Note this is not quite the same as tuning the free running oscillator
The sensitivity to the injected signal can be optimised if the 32768Hz
oscillator is suitably designed.
The 32768Hz injection locked oscillator output can be used to injection
lock another 32768Hz crystal oscillator whose design cannot be optimised
for direct injection locking to a 10MHz signal.
More information about the time-nuts