Back in 1997 when working on a car project I saw several failures of AD595 Thermocouple converter chips due to sound. In all cases the bond wire to pin 8 of the CERDIP package failed, presumably due to resonance (I took the top of the chips to check) A blob of non acid cure RTV silicone rubber on the chip seemed to cure it. The box with the AD595s was mounted in the rear of the car between the exhaust plumes of two 20,000lb thrust re-heated jet engines so the sound level was quite high :-) The box is in the open wheel compartment seen here http://upload.wikimedia.org/wikipedia/commons/4/41/ThrustSSC_back.jpg Robert G8RPI.
________________________________ From: Bob Camp <li...@rtty.us> To: Tom Van Baak <t...@leapsecond.com>; Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Friday, 28 March 2014, 11:33 Subject: Re: [time-nuts] FEI-5660 Rubidium Oscillator Hi Crystals are susceptible to vibration. That’s pretty well documented. They have resonances in the mount structure. They have a 2G tip sensitivity. Audio when it “impacts” an oscillator induces vibration. If your noise source is a rocket engine, then the vibration is “non trivial”. You do indeed see phase noise on the oscillator from audio … Bob On Mar 27, 2014, at 11:42 PM, Tom Van Baak <t...@leapsecond.com> wrote: >> More seriously, I'm assuming you're advocating rock for the thermal mass >> and/or mechanical. What about a 100 pound box of sand? > > Mechanical. I figured a OCXO might be susceptible to microphonics, especially > in a recording studio. But if it's down to the level of 1 lsb of the digital > sampling, then no worries. > > Has anyone on the list ever measured this effect, even on a cheap crystal? > > /tvb > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
