Low phase jitter in L-band XO: frequency multiplication of regeneration

This paper presents the results of crystal oscillator (XO) development, which generates an output signal in the L-band. The conditions of BJT stage operation allow simultaneous forming, a fundamental mode of quartz crystal oscillation, as well as, considerable amplitude of required harmonic. It´s known, that the interaction of a basic oscillation with its harmonics is a reason for additional phase shifts in an oscillating loop and stability decrease in stability of oscillator. However, these researches have shown, that use of a regenerative operation mode in oscillating stage on a required harmonics allows not only to gain sufficient amplitude of L-band signal, but it also allows us to realize a high loaded Q-factor on a fundamental mode of a quartz resonator. The obtained power spectral density of a phase noise S_φ(1 kHz)=-110 dBc/Hz for 1 GHz oscillator output signal shows the advantages of the proposed method. It extends XO application range into L-band and allows to get phase jitter lower than 1 ps for large jitter bandwidth.