Problem with VCO output (as there is no buffer)
i should match its output for maximum power transfer
i measured its output impedence, and i put a matching load Zload = Zout*
but when i did that, no output from VCO and the oscillation is dead.
why does this happened?
mohamedabouzied
I think you have to match the VCO after buffer with capacitive input. Because the load has big influence on VCO feedback as consequence on VCO oscillation.
u mean to use a buffer between the VCO and and outer world?
that buffer is an RF buffer so, it is hard to implement.
also, should i match between the VCO and the buffer?
do u have a good paper or toturial to implement this buffer?
and does that buffer have an inductor?
another bad thing?
thanx for replay
mohamedabouzied
Here are a VCO with buffer
but there is 2 coils
is that ok?
i mean a coil is a big block, is there a way to overcome or replace it?
thanx alot for your replay
mohamedavouzied
It depends on your specification... If you have enough area - use inductors, if not - use resistors. Try both to find best suited...
the buffer can be done , without coils , it can be comon source amplifer , or common drain , then u can make this drive , the output world
never match the Zof the VCO . alos the Z of the VCO change , coz the VCO is hard nonlinear circuit
khouly