Full wave rectifier as Saw-to-Tri converter

[Martin Czech]

I don't understand the circuit. 
What does happen with the first OPAMP if feed with a very
slow saw ? No dc feedback, should go to rail.
For negative input there is some feedback via diode,
but again, what does happen if the cap is already charged?

I don't want to say that this circuit doesn't work,
but I fell that it is frequency dependend (low end).

???


m.c.