RUBIDIUM ATOMIC FREQUENCY STANDARDS

MODEL FE-5650A, FE-5652A, 5660A, FE-5680A

RUBIDIUM ATOMIC FREQUENCY STANDARDS MODEL FE-5650A, FE-5652A, 5660A, FE-5680A Rubidium Frequency Standards uses the property of atomic resonance in a Rubidium Physics Package to control the output frequency of a 10+ MHz Voltage Controlled Crystal Oscillator (VCXO) via a Frequency Lock Loop (FLL).

The FLL functional blocks 21 1.0 Vrms Output of an RF Generator, Lock-in Amplifier and the Rubidium Physics Package. Frequency locking of the VCXO is accomplished by operating the Rubidium Physics Package as a frequency discriminator, i.e., departures of a frequency from an input signal (50.255+ MHz from the VCXO) from a defined center frequency (Rubidium atomic resonance) produce a DC output signal (control voltage). Once the FLL has been established, the system generates a clicked indication which can be monitored on pin 3.

Depending on the option selected, the 50.255+ MHz output is used as the clock input for the DDS within the Synthesizer, the Digital Programmable Synthesizer Amplifier. Rubidium Physics Package utilizes the ground-state hyperfine transition of the Rubidium atom. In order to use this atomic transition, the Rubidium Physics Package incorporates a Rubidium cell, Rubidium and servo electronics . The VCXO is locked to the Rubidium atomic resonance at 6.8+ GHz.

The VCXO frequency of 50.255+ MHz is an exact sub-multiple (x136) of the atomic resonance frequency at 6.8+ GHz. The signal is generated in the physics package. Light from the Rubidium lamp, produced by an excited plasma, is filtered and passed through the Rubidium resonance cell where it interacts with Rubidium atoms in the plasma. After passing through the resonance cell, this light is incident upon a photocell.

When the applied microwave frequency is equal to 6.8+ GHz, the Rubidium atoms are resonated by the microwave field in the cavity. The decrease in light, when the microwave frequency is equal to the Rubidium frequency, is then converted electronically to an error signal with phase and amplitude information used to steer the VCXO via its control voltage and keep it on frequency at 50.255+ MHz. The frequencies for Options 02 are provided by the Digital Programmable Synthesizer. Option 02 is an RS -232 digitally controlled output with a frequency range of 2 x 10-7 at a resolution of 5 x 10-12.

Key Features

	Extremely small: 3x3x1.4 inches Digitally programmable to 1x10(-13) Frequency: 1 Hz to 20 MHz & 50.255+ MHz Stability over temperature: 3x10(-10) Stability: 1.4x10(-11)/ 2x10(-11)/day 2x10(-9)/year
	Temperature range: -40deg C to +85degC Stability over temperature: 5x10(-11) Digitally programmable to 1x10(-13) Frequency: 1 Hz to 20 MHz * Fast Warm-up: <5 min. Stability: To 5x10(-12)/ 2x10(-10)/year
	Standard output frequency is 5 or 10 MHz Short term: Allan Deviation 3x10(-11)/ Long term: Aging 5x10(-11)/month Temperature: 3x10(-10), -5 to +50 deg C
	FE-5658A Features Extremely low silhouette: less than 1.0 inch Stability over temperature: 5x10(-11) Digitally programmable to 1x10(-13) Frequency: 1 Hz to 20 MHz Fast Warm-up: <5 min. Stability: To 5x10(-12)/ to 2x10(-10)/year

Further Information

For further information regarding any of the FE products and the full range of services that Steatite can offer you, please call our team on 01527 406881. Alternatively, you can request addition information on-line using our information request form.