Re: [time-nuts] HP History with Dymec: "Becoming Hewlett Packard. Why Strategic Leadership Matters"
Speaking of books about HP, I highly recommend "Bill and Dave: How Hewlett and Packard Built the Worlds Greatest Company". It covers the history of HP including the development of many of the landmark pieces of test equipment, the HP business model, and the company expansion from the garage to a multi-national corporation.. Very approachable- reads almost like a novel. Being a big HP fan, I can't say enough good about the book. Tom On Wed, 1/23/19, Rice, Hugh (IPH Writing Systems) wrote: Subject: [time-nuts] HP History with Dymec: "Becoming Hewlett Packard. Why Strategic Leadership Matters" To: "time-nuts@lists.febo.com" Date: Wednesday, January 23, 2019, 5:41 PM Hello Time Nuts, Being a bit new to HP (only 35 years), I never head of Dymec before. A quick Google search yielded this link, which is an excerpt from the book "Becoming Hewlett Packard, Why Strategic Leadership Matters." You can read about 10 pages of the book from the preview, which talks about HPs creation of the Dymec corporation, which then became a division. Scroll back to page 102 for some context. https://books.google.com.sg/books?id=Zr1jDQAAQBAJ=PA104=PA104=dymec+company+history=bl=Q_66Bj1viA=ACfU3U2ITctr8yhZ_yXWCQ_v8qWClLXafw=en=X=2ahUKEwixtsCj-oTgAhXJh3AKHXd3DqMQ6AEwDHoECAUQAQ#v=onepage=dymec%20company%20history=false I plan to buy a copy of the book and read it on my trip to Hong Kong this weekend. If it is interesting, I'll write a quick review for you all. Tom V: Let us know if we are wandering too far off topic for time-nuts. Hugh Rice ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] A silly question ...
This is assuming that your oscilloscope is set at 100 nS/DIV. My Tek 2465A will sweep at 5 nS/DIV normally, and 500 pS/DIV when the sweep is set to X10. If I'm figuring correctly, this will allow 1e-12 in 432 seconds. I use a stop watch to time the zero crossings of the sine wave - something like: Assuming the wave moved 5 divisions in 185 seconds: (500 pS * 5 DIV)/185 seconds = 13.5e-12 ppm. (I think this is correct. tvb?) Since a 10 MHz sine wave tends to look like a flat line at 500 pS/DIV, I often set the vertical V/DIV to 2 mV/DIV. Tom From: Tom Van Baak To: Discussion of precise time and frequency measurement Sent: Thursday, September 27, 2018 11:19 AM Subject: Re: [time-nuts] A silly question ... > "I think", that if for example, it takes 1 second to drift one cycle, > that works out at 0.1 ppm. If it takes 2 seconds, it's 0.05 ppm, if it > takes 5 seconds, it's 0.02 ppm etc. Is that correct? Yes. At 10 MHz one full cycle is 100 ns. So if the cycles are drifting by 100 ns per second that's 100e-9 s / 1 s = 1e-7 = 0.1 ppm. At these levels of frequency accuracy, using a 'scope is plenty good enough. In fact, it's more educational and somehow more enjoyable to watch analog sinewaves drift past each other than it is to see the digital display of boring frequency counter. Where the 'scope method starts to break down is when the frequency error gets down to the ppb level. At 1e-9 it will take 100 s for the waveforms to drift by one cycle. And at 1e-12 you would have to wait an entire day (100 ns / 86400 s = 1.157e-12). On the other hand, with frequency offsets this low you don't have to sit there the whole time. One trick would be to take a photo of the 'scope once an hour, or, say, once every 1000 s. If you played that back at 1 fps you'd have a 1000x "time magnifier". /tvb ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
