Help me! I need explanation! Robert Lutwak wrote:
>With that said, the Perkin-Elmer rubidium on the IIR >satellites is an outstanding clock, unquestionably the >best rubidium ever manufactured for any application, >with short-term stability an order-of-magnitude better >than the IIF cesiums. The drift is also remarkably >low for a rubidium oscillator, compared to commercial >rubidium, and, with daily updates, they will >outperform the cesiums, though the cesiums will beat >them outside of a week or so. Well, i've got the PDF brochure for the Perkin-Elmer, and it's indiscutably an outstandingly superb Rubidium frequency standard (458 000 hours MTBF!!!), but there's something that ticks me here, and i've seen it on other rubidium standards. Let me explain: On the brochure, the output frequency is 13.40134393 MHz and in the RF section of the block schematic, we can see that the 13.40134393 MHz OCXO is multiplied 510 times (classic x6 followed by an SRD x85) before driving the physics. If my calculator is OK, that gives me 6834685404.3 Hz. However, the hyperfine transition of Rubidium is at 6834682612.8 Hz! A difference of 2791.5 Hz (0.40843 PPM)!!!! I don't understand! That's not a Lada, that's a "Ferrari" grade standard! As i wrote earlier, i've seen a similar difference on another (Efratom, if i remember) Rb standard! Can someone explain me? I don't understand! Thanks for your attention! Normand Martel Montreal, Canada __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
