Hi,
I was trying to design an FM transmitter and there is one thing that is puzzling me somewhat.
I know that I will have to build an oscillator running at a certain frequency. I want to make a BJT based hartley oscillator. I will have to give an audio signal as an input to the RF oscillator. Meaning that the oscillator will change its frequency. However, the tank circuit in the hartley would remain at more or less the same resonating frequency: 1/(2*pi*sqrt(LC)). So why:
1. would the oscillating frequency of the oscillator change in the first place.
2. if it would change then there ought to be a loss in efficiency for input frequencies that make the oscillator shift too far from its resonant frequency. Am I right in assuming that this loss would be negligible since we are RF frequency would be much larger than the audio frequency?.
Also, I have been trying to find some site which would explain hartley and colpitts oscillators in detail but I havent been able to...could somebody help in this regard.
thanks...