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FM transmitter Audioguru

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rimEP

New Member
Hello,
I've been trying to simulate Audioguru's FM transmitter with Proteus then with LT spice but I have encountered numerous problems. First of all, this is my first try with LT spice. Secondly I can't find the LM2931a regulator. Also I don't know how to run the simulation because I always get a blank diagram as an output.
I joined my draft on Lt spice and Audioguru's model picture to this message.
I will be very grateful if you could help me.
 

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ronsimpson

Well-Known Member
Most Helpful Member
I do not have it working but some of the errors are fixed.
I added a 5V and a 9V voltage(s)
There was a resistor with out value.
I fixed the two capacitors at 30pF.

No time now. Maybe some one can make it work.
 

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ronsimpson

Well-Known Member
Most Helpful Member
Right click on each inductor.
Clear all windows except inductance. 1nH The parallel resistance should be blank. The parallel cap should be 1pF or blank.
 

audioguru

Well-Known Member
Most Helpful Member
The monsterous very high power inductors you used in your sim do nothing at very high radio frequencies. I made the inductors myself and they work perfectly.

Here is my sim of the RF circuit with its parts tweaked to work the best:
 

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rimEP

New Member
I erased all the other values in my components. How can I define what other values to put?
 

audioguru

Well-Known Member
Most Helpful Member
Your TRAN command does not delay the start time to save data so the oscillator is not even oscillating yet when your sim stops. The oscillation is good after a start delay of about 4000ns, look at the TRAN command on my sim.

Here is my TRAN command:
 

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