Phase-Lock-Loop vs Injection Locking

  • Thread starter Fischer777
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In summary, the individual is working on a school project that involves sending a synchronizing signal to an oscillator on a receiver. They have discovered that injection-locking may be easier to use than a circuit involving multiple components, but are unsure why it is not commonly used compared to PLLs. The conversation also touches on the differences between the two methods in terms of controlling and predicting harmonics.
  • #1
Fischer777
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Sorry it's been a while since I posed here. I'm working on a project for school that will involve sending a synchronizing signal to an oscillator on a reciever, which I know often uses a phase-lock-loop. However, I was doing some reading on injection-locking, and it seems that it would be easier to utilize than a circuit involving several mixers, filters, and variable reactance components. But dispite this I can't find any instances where it's used in a practical circuit, so it somehow seems to be less preferable than PLLs. I'm wondering if anyone knows why this is the case (why PLL are preferred over injection-locking).

Thanks!
 
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  • #2
Injection locking will lock the p'th harmonic of an oscillator to the q'th harmonic of a reference signal. Just which integer p/q ratio of harmonics can be hard to control or predict, and sometimes does not matter if drift is the only concern.

A PLL synthesiser has well defined integer ratio p/q, (a swallow counter), that locks a local VCO to a predictable frequency.
 
  • #3
Okay, thanks! It makes more sense now.
 
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