At resonance, an LC looks pure resistive. For a parallel LC, sample the voltage across the LC and the drive current, and tweek the frequency until they are in-phase.
For a series LC, sample the voltage across the L or C and tweek as above. If you want to do it analog, dither the frequency a bit. With the quardature of the sweep signal as reference for a lock-in. The output of thye L-I is the tuning signal. (Roughly Pound Locking) YMMV, -John =============== > Hi all, > > I'm thinking about an upcoming project, if this is off topic please > disregard or contact me off list. :) > > I have a large LC tank, with a very lossy inductor. Being driven by a > pulse width push pull driver, that is digitally controlled. The driver > circuit will couple through a N:1 transformer. I need to be able to > adjust the push/pull driver frequency to match the frequency of the tank > circuit. (See frequency/time is involved :) ) The tank components can > vary and are not adjustable, so the drive frequency needs to vary. > > I'm thinking some sort of a phase detector may be the way to go. I'm > just not sure were to sample the V and I signals to look for phase > differences, or where to get a good clean reference from. > > So the question is, when actively driving a tank circuit, how do you > know you are driving it with the same frequency ad the same phase it > naturally oscillates at. > > Any thoughts, suggestions, or readily available papers you guy could > point me to? > > Thanks! > Dan > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
