When turned on, the processor applies a voltage to the varactor corresponding to the last lockedВ value. TheВ processor sweeps the RF synthesizer, synchronously detects the optical signal from the physics package, and servos the 10В MHz crystal oscillator to the rubidium transition via a 22-bit DAC and aВ varactor. The PRS10 uses a microcontroller, clocked at 10В MHz, to control all aspects of operation and to allow diagnostics, measurement, and closed case calibration via an RS-232 interface. TheВ crystal oscillator is stabilized to the rubidium transition by detecting the light dip while sweeping an RF frequency synthesizer (referenced to the crystal) through the transitionВ frequency. TheВ amount of light from a rubidium discharge lamp that reaches a photodetector through a resonance cell will drop by about 0.1В % when the rubidium vapor in the resonance cell is exposed to microwave power near the transitionВ frequency. ItsВ design provides the lowest phase noise, greatest versatility, and easiest path to system integration of any rubidium frequency standardВ available.ДЄll commercial rubidium frequency standards operate by disciplining a crystal oscillator to the hyperfine transition at 6.834,682,612В GHz inВ rubidium. The PRS10 establishes a new level of features and performance in atomic frequencyВ standards. ThisВ feature can provide StratumВ 1 performance at a very lowВ cost. TheseВ values may be reported back via RS-232, or used to phase-lock the unit to an external reference (such as GPS) with time constants of severalВ hours. The PRS10 can time-tag an external 1В pps input with 1В nsВ resolution. ItsВ low aging rate makes it an excellent timebase for precision frequencyВ measurements.

TheВ unit's short-term stability and low environmental coefficients make it an ideal component for networkВ synchronization. TheВ phase noise of the 10В MHz output is low enough to be used as the reference source forВ synthesizers. TheВ device fulfills a variety of communication, synchronization and instrumentationВ requirements. The PRS10 is an ultra-low phase noise, 10В MHz rubidium-disciplined crystalВ oscillator.

10 mhz crystal filter design