I stumbled across this United States Patent 7236062 granted to Broadcom last year
- A method for reducing noise in a circuit, the method comprising: receiving a first voltage at a positive potential input of an oscillator circuit comprising an oscillator core and a buffer coupled to an output of said oscillator core; filtering noise from a second voltage to generate said first voltage using a resistor coupled between said positive potential input of said oscillator circuit and a source of said second voltage, and a capacitor coupled between said positive potential input of said oscillator circuit and a ground of said oscillator circuit; and compensating for a voltage drop across said resistor by varying said second voltage.
I mean wow, it would never have occurred to me to use an R C filter on the supply to an oscillator or that in doing so I might have to compensate for the voltage drop across the resistor.