Leeson's Oscillator Noise Model
Estimate single sideband oscillator noise characteristics.
Ln (dBc)
Δf(Hz)
Click or touch the plot above to read the values
| Δf = | - frequency distance from the oscillator frequency | |
|---|---|---|
| Ln = | - single-sideband phase noise spectrum | |
| QL= | - Q-factor of the resonator |
Enter oscillation frequency to find Q-factor of the resonator, you can use SI suffixes in your numbers e.g. 10k would be 10 kilo. Capitalization matters, as 1m would be 1 milli and 1M would be 1 mega.
Description:
Calculations are based on the Leeson oscillator noise model, which gets two asymptotic appearances dependent on whether fa is smaller or larger than half the 3dB bandwidth BW3dB of the resonance circuit in the oscillator.
Ln (Δf)=Feff k T / 2Po {1+fa/Δf} {1+(BW3dB/2Δf)2} [Hz-1],
where
Feff - effective noise figure that describes the amplifier under large signal sinusoidal excitation.
Po - output power of the oscillator.
T0 = 290 K, k ≈ 1.38×10−23 J/K.