AW: Re: Switched Capacitor Phase Shifters

[Haible_Juergen#Tel2743]

> Check out US Pat. No. 4,306,480, by Frank Eventoff and Serge A. 
Tcherepnin.
> This describes a VC phase shift stage using 1/4 of a LM3900.  These stages
> can apparently be cascaded, resulting in a 4-stage phase shifter using one
> chip (that costs about $.58), plus caps, resistors, etc.  No LDR's, no
> FET's, no OTA's.

Sounds almost too good to be true - otah I'd credit this ol' wizard with
almost everything ...
How can I look at these documents?

JH.