i need to design an rc phase shift osc. at a freq of 1khz (say)
the frequency of osc. for an opamp based osc., is 1/(2piRC*sqrt(6) if we use 3 rc networks.
Now i choose R and C accordingly. Now since v use 3 RC lead networks, each must be designed to produce a phase shift of 60 degrees.
but for the chosen values of R and C the phase contribution from each network turns out to be 90-arctan(1/sqrt(6)) which does not give 60 degrees.
plz let me know where i have gone wrong....
the frequency of osc. for an opamp based osc., is 1/(2piRC*sqrt(6) if we use 3 rc networks.
Now i choose R and C accordingly. Now since v use 3 RC lead networks, each must be designed to produce a phase shift of 60 degrees.
but for the chosen values of R and C the phase contribution from each network turns out to be 90-arctan(1/sqrt(6)) which does not give 60 degrees.
plz let me know where i have gone wrong....