A novel voltage controlled high frequency crystal oscillator circuits

Abstract

We report an active mode-coupled 622 MHz crystal oscillator circuit as a cost-effective alternative of surface acoustic wave (SAW) resonator oscillator. Experimental evaluation of the implemented active mode-coupling mechanism shows that the latter may provide a superior performance in comparison with commercially available expensive SAW resonator based reference frequency standards. The typical measured phase noise for 622 MHz voltage controlled crystal oscillator (VCXO) at 10 kHz offset is better than -156 dBc/Hz with operating DC bias of 8 V and 23 mA.

A Low Phase Noise Crystal Oscillator with a Fast Start-Up Bandgap Reference for WLAN Applications

“…Since its invention by Cady [1] in 1923, the crystal oscillator has undergone significant developments, including the resolution of aging issues in the 1940s and 1950s [2], the achievement of low-power operation in the 1970s and 1980s [3,4], and widespread use in wireless communications [5], navigation [6], satellites [7], and radar [8], among other fields. In wireless communication applications, such as radio frequency transceivers [9,10] and digital circuits [11,12], crystal oscillators are utilized to generate stable and accurate reference clocks.…”