hyy95 wrote on Mar 17th, 2009, 7:25pm:why can it force the transistors into active region?
Since it forces input and output to same voltage.
hyy95 wrote on Mar 17th, 2009, 7:25pm:why it's value should be high?
Since it is negative feedback resistor.
hyy95 wrote on Mar 17th, 2009, 7:25pm:how does a low value Rf degrade the frequency stability?
Rather if Rf is too small, oscillation will not start up.
hyy95 wrote on Mar 17th, 2009, 7:25pm:how does a low value Rf increase the current?
It Rf is too small enough not to start up oscillation, static DC current is consumed at inverter where both NMOS and PMOS are on state.
hyy95 wrote on Mar 17th, 2009, 7:25pm:how can we find the best value of Rf?
It depends on oscillation margin and drive current for crystal.