XPost: sci.electronics.design   
   From: donnyduck@gmail.com   
      
   Like any PLL or ILL or AGC , you only have samples to correction error   
   and never "continuous" correction unless integrated to a DC level. It is   
   a discontinuous error correction with a filter to hold between inputs.   
      
   There are many ways to correct error by limiting the gain > 1 yet   
   ensuring it can reach 1 to oscillate.  S/H, non-linear soft limiters,   
   filters, peak detectors/comparators. It all depends on your specs for   
   lock-in time and THD/IMD specs of the sine wave.   
      
    >  > There's no requirement that the amplitude regulation be continuous.   
   >   
   > Phil Hobbs   
   >   
      
   --   
   Cheers,   
   Tony Stewart   N. Of Toronto   
   EE since 1975 practising retirement since 2004   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)