[time-nuts] injection locking crystal oscillator

[ed breya]

In this case, it appears what you want is choice of two 10 MHz reference 
sources, and not any frequency conversion. Instead of injection locking, 
why not just switch between one or the other? It's quite simple to 
externally drive the built-in oscillator in most ICs. You can make the 
circuits however necessary to disable the crystal, and connect the 
external drive, manually, or automatically - it doesn't take a lot. Then 
there will be no issue of possible signal complications associated with 
injection locking.

Ed