Tracor 304D

The 304D Rubidium Frequency Standard is a compact, rugged atomic secondary frequency standard for general use. Utilizes stable crystal oscillator, frequency-controlled by atomic resonance of rubidium. Time Scale Selector allows quick change of time scale value or convenient calibration offsets. Initial frequency setting is 1x10E-11 relative to the time scale required. Outputs of 5MHz, 1MHz, and 100kHz sinewave are available at both front and rear panels. Signal level 1 volt RMS into 50 ohms. Stability is < 2x10E-11/month.