RadioRon
Well-Known Member
Harros said:Well, for the transmitter part, the output swing of the crystal oscillator is around 4Vpp, so, is there any suitable amplifier for this situation? This is because I want to increase the transmit power of the transmitter... Or should I use voltage divider on the output of the crystal oscillator and implement the small signal amplifier (just like the type that i build for the receiver) to increase the transmitter power?
I would use no voltage divider or perhaps a modest voltage division ratio, but you don't need to attenuate the signal. A better approach is to use the same transistor in your amplifier but alter the bias point by adjusting the resistor values. When you have a lot of voltage swing available like this and you aren't carrying modulation on the carrier, a simple class C bias is appropriate. You can achieve this by removing the base bias resistors and simply letting the input signal turn the transistor on and off. You could also reduce the emitter resistor a little bit too so that more output power can be had.