[time-nuts] xtal oscillator phase noise

[Henk ten Pierick]

Hello,

Some questions on xtal oscillator phase noise. Attached the  
measurement result of my series resonant xtal oscillator.
It is a class A, ibias 5 mA, Ixtal 1 mArms. Transistor selected for  
low Rbb' 20 Ohm, Ft 100MHz. Reference voltage 5V from an ADR445,  
filtered with 10uF folie cap. Phase noise target -130dBc at 10Hz.

1. Is series resonant better or easier to engineer than parallel  
resonant?

2. Where should I have 20 dB/decade and where 30 B/decade?

3. Some suggestions for the next 25dB?

4. Is there more to learn from the attached picture?

regards,

Henk

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