Inductive Balanse, PWM sine and Coil

[TheWizard]

I can PWM (pulse width modulation) create sine frequency's (Base:12.5 kHz, PWM period:100kHz)

How to choice and calculate IB Coil and coil filter to get best parameters for the transmitter...

[Max]

I can PWM (pulse width modulation) create sine frequency's (Base:12.5 kHz, PWM period:100kHz)

How to choice and calculate IB Coil and coil filter to get best parameters for the transmitter...

Hi,
why don't use R/2R ladder for this ? I will do this way... using some op amp to get more output current there...

Higher Q means you will radiate more energy there... you need a near-to resonant tank I think... but not resonant, of course, to avoid well known problems. I don't see that difficault if you can already create a sinus wave using PWM.

One question: Cannot you use square signal to drive (using some transistor power stage) directly the LC tank ?

Kind regards,
Max

[TheWizard]

I am "barefoot" with LC circuits...

One question: Cannot you use square signal to drive (using some transistor power stage) directly the LC tank ?

Maybe will test later and is easy to change PWM with square.
I see (in google) serial resonanse (LC) and square for VCC +5v output by coil is 150-300V

why don't use R/2R ladder for this ?

With PWM, I save CPU time for other calculations and PWM is easy for driver amplification

Attachment is signal filtered only with RC...

[Qiaozhi]

One question: Cannot you use square signal to drive (using some transistor power stage) directly the LC tank ?

Kind regards,
Max

I seem to remember that Ivconic had a nice simple circuit to do this, and you could adjust the frequency.

[TheWizard]

Attachment:
MOSFET Full-Bridge Driver(~1$)
Coil (unknow) not tuned for resonanse...
First harmonics at -40dB,
Sample Rate harmonics at -72dB
(soundcard records and graphic)

Now the question is: Parallel or Serial resonanse?