Reactance FM modulator

Thread Starter

Envy

Joined Aug 15, 2013
3
Hi,
I'm trying to make a simulation of a reactance FM modulator. I've got a schematic but I don't really know which values I should use for the components.
Also if anyone has a great tutorial for making one, it is always welcome.
In the schematic a Clapp-oscillator is used, but I think it's also possible to use a Colpitts or a Hartley.

Thanks in advance
 

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DickCappels

Joined Aug 21, 2008
10,152

The circuit above is essentially the same thing. Its a Colpitts and instead of a separate transistor as the reactance modulated device, the capacitance of the oscillator transistor is modulated directly by the small differences in base-collector voltage caused by the signal from the microphone.

Additionally, if you Google Varactor Tuned Oscillator, you will find many reactance tuned oscillators.
 

Thread Starter

Envy

Joined Aug 15, 2013
3
Thanks for the fast reply! Can you give the link of this circuit so I can have a better look at the values?
 
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