HYDROGEN FREQUENCY STANDARD Russian patent published in 2000 - IPC

FIELD: high-stability signal sources. SUBSTANCE: hydrogen frequency standard has hydrogen producer and crystal oscillator incorporating phase-locked loop (PLL) system operating in response to signal coming from hydrogen producer. Hydrogen producer resonator frequency is tuned to spectral line top using line Q-factor periodic modulation method. Automatic tuning unit of resonator is connected through switching device to output of PLL phase detector. Automatic tuning unit of resonator has series-connected selective filter, analog-to-digital converter, digital synchronous detector, and digital- to-analog converter. Synchronous detector is program-controlled device. Provision is made for discriminating resonator detuning signal from frequency control circuit of crystal oscillator which makes it possible to dispense with auxiliary hydrogen producer in automatic tuning system of resonator. EFFECT: reduced relative frequency instability of frequency standard. 2 cl, 4 dwg