FM transmitter sinulation required?

[shazaidy]

Hi. I need FM transmitter proteus simulation. Can anyone please provide it to me?

 

[kubeek]

Sorry, what? What is the problem with choosing some circuit, putting it into proteus and simulating it?

 

[unclejed613]

he wants it already done and wrapped in a pretty package...

i have to agree with you, it's easy to draw a schematic and run it. problem is, there's a huge difference between a sim and real live circuits.... especially at 100Mhz, where a 1" trace on a PC board (or piece of wire) can make it not work....

 

[shazaidy]

I have made different simulations but none of them is giving the required output. I connected an oscilloscope instead of the antenna to get the modulated signal but the output at oscilloscope is certainly not the correct one. I am attaching the snapshot of the output.

 

[ronv]

Maybe you can post your schematic.

 

[kubeek]

LOL, what? Do you want me to post some other picture of scope and claim that I solved all your problems by changing C131?
Please post your schematic, and say what you expected and what you measured.

 

[audioguru]

Proteus? Hardly anybody uses it anymore.
There are too many old Simulation programs. Most of us use the free LTspiceIV program.

 

[unclejed613]

all i can tell from the scope picture is that the OP has a 1khz (not 100Mhz) sine wave, and something is turning on and off in the second trace

 

[shazaidy]

View attachment fm transmitter.zip

This is the simulation I am using.

 

[kubeek]

Better post a picture.

 

[unclejed613]

DSN files don;t do us any good.... do a screen shot of the schematic, and don't zip it.

 

[shazaidy]

 

[audioguru]

The schematic has no contrast, has a dark background and is covered with a grid. Things are difficult to see.
It looks like a simple FM transmitter.

The modulation level is 150 or 500 times too high so the preamp transistor is clipping and is causing the oscillator to turn on and off at the modulation frequency.
Use a modulation level of 5mV (like from a microphone).

An oscilloscope will not show the tiny frequency change in a VHF FM transmitter. At maximum modulation the frequency changes only 75kHz which is almost nothing at 100MHz. You might see the small amount of AM produced by this circuit.