[time-nuts] IL waveforms

Kit Scally kScally at BYTECAN.com.au
Thu Feb 11 22:08:17 UTC 2010


Joop,

Indeed !  
During lab evaluation, a sine wave locking source required much greater
power (15-20dB IIRC) to achieve lock.  Further, lock limits were almost
impossible to discern with any degree of confidence.  
With a square wave, there were distinctive step jumps when approaching
lock & going out of lock.

Kit
VK2LL

Kit VK2LL wrote:
>Theory suggests that lock sensitivity could be improved in this
instance
>if the 10MHz duty cycle was changed from 1:1 to 6 or 7:1, the idea
being
>that the narrower pulse should be <0.5 period of the frequency of the
>oscillator to be locked.  

Joop wrote:
Thinking this way of injection locking, it makes sense to increase
harmonic content of the injected signal. In essence it will then not
lock
onto the fundamental frequency, but on some harmonic part of it. In my
SPICE investigation I injected a clean sine signal. Perhaps I should try
with some clipped or digital signal.
That might also explain why James G1PVZ was so successful. The bottom
2N918 might cause a lot of harmonics if driven into the collector
cut-off.



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