The A1000A is based on the E10-LNA Very Low Noise Rubidium Oscillator Module which is a sub miniature atomic clock with Quartzlock’s ‘active noise filter’ technology built in. This rubidium oscillator has 100 x less drift than OCXO’s. With short term stability of 0.002ppb/s @ 100s this rubidium oscillator provides significant improvements in performance over other rubidium components.