Low phase noise VCO

Hi,

In my project, I drive an oscillating device (oscillator) with an VCO reference signal. In order to lock the oscillator's frequency, a PLL is employed. To keep the device oscillating the input frequency needs to be hit at least as precise as 0.005 Hz.

The problem, though, when the oscillator is changed, its center frequency changes, too. It can be in the range between 11.75kHz-12kHz.

Because of other clocks that need to be synchronized and generated, the VCO's output frequency must be in the range 13.865-14.16 MHz. Actually, a VCXO would fit my needs best to tune the frequency as accurate as 5.9 Hz at 14 MHz (0.005 Hz at 12kHz). However, if I pick a VCXO for say

So, I need a VCO whose center freqency is coarse adjustable in a relatively wide band (13.8-14.2 MHz) and it should have a fine frequency tuning resolution using the input voltage.

Has anyone an idea what VCO could fit for this?

Thanks,

Stefan

Check out Randy Rhea's VCO design book, has a nice colpitts oscillator in there that would work.

I posted a pdf file on oscillator design in alt.binaries.schematics.electronic written by Dr. Rhodes.