Discrete quadrature oscillator possible?

Hello I consider this circuit
http://www.seekic.com/circuit_diagra...ivibrator.html
Can it produce 90 degrees phase difference between it's outputs or 180 degrees?

Is it possible to scale it for HF frequencies? <30MHz

A converted crystal configuration could also be used based on these circuits
https://www.google.gr/imgres?imgurl=...DrwQMwgdKAMwAw
http://www.seekic.com/circuit_diagra...STABILITY.html
http://www.eleccircuit.com/symmetric...lator-circuit/

Probably 90°, very roughly. I predict that the circuit will generate neither exact phase shifts nor symmetrical waveforms, in so far it may be partly or completely unsuitable for your quadrature oscillator application. It's funny how these sites claim circuit properties without even telling component values.

Instead of expecting others to answer your questions, you would want to evaluate the circuit behavior with a simulator.

It phase difference is not within 1 degree or so exact and if amplitudes are not exactly equal, this is of no use in quadrature circuits.
I will try to simulate it in ltspice.



Ok I did a simulation on ltspice, I hope I got it right.
The value of R and C is arbitrary
I got the next results.
Any suggestion about more optimal values is appreciated.

I am not sure about the degrees accuracy too, how can I measure them and how values affect theese.