Induction planars

[phase_accurate]

Who was talking of magnetless drivers ?????

Regards

Charles

[APi]

Originally posted by misterears
A true magnetless induction transducer is unfortunately a frequency doubler since it has no way of discriminating the polarity of the induced field (which is why a permanent magnet is needed as a reference unchanging field).

True. But maybe it's possible to predistort the signal in the way that current through the coil follows the next formula:

a x V(t) = I x dI/(dt) , where

a = scale factor
V(t) = signal level as a function of time
I = current from PA ~ first magnetic field
dI/dt = derivative of the current ~ derivative of the second magnetic field

(dI/dt ~ induced voltage over almost constant resistance ~ induced curent ~ second magnetic field. )

I see this very hard to realize by analog predistorter since constant signal level cause more or less t^(1/2) shaped function for I. But digital... GNU Octave would be the easiest way to test such algorithms?

One other thing... To make system more effective one could generate more eddy currents by modulating signal with some sort of (triangle?) pulses above hearing frequency ~20kHz. Er....

[Jeb-D.]

Or perhaps the driver would need some DC offset, Class A style.