"new" oscilator core

[Martin Czech]

:::This is very similiar to the circuit for Hewlett Packard 3311A
:::Function Generator.  
:::
:::Reference: "Compact Function Generator with Enhanced Capability/Cost
:::Ratio", E. Harry Heflin, the Hewlett Packard Journal, July 1973.  An
:::article I happen to have saved for a very long time.
:::
:::The HP version uses slightly different technology, but it's basically
:::the same idea.  The major difference is that a diode bridge is used to
:::switch the positive and negative currents into the cap.

Oh, I remember such diode bridges were used in some Bob Pease column,
"What's all the femtoampere stuff anyhow" or so for a tri oscillator,
this in turn was feed into a cap, giving very small dc currents during the slope
(differentiating the triangle). Uncle Bob explained what type of diode
to use, I think 1N4148 was banned because of extreme leakage.

m.c.