[email protected] said: > My actual application is as a quick cool demo showing what I can do with > this gear in my garage when people go "why"?
What's the geekiness level of your target audience? I'd probably start with a scope. I think that would be easier to explain to not-quite-geeks. Look at the pulse coming out of your GPSDO and also after going through 100 feet of coax. For geeks, you could measure the delay through 100 feet of coax, then compute the velocity (assuming the length is correct) and see if that matched the specs for the velocity of the coax. Assuming your scope cooperates, you could also look at the next PPS and use that to calibrate the osc/clock in your scope. (Last time I checked, mine was off by 6 ppm.) A 5370B is (much) more accurate at measuring the delay than a scope. But it doesn't give you the pretty picture and may be way off if your signal has a slow rise time and the trigger levels are not right. It might be fun to analyze the possible errors in that sort of setup and compare them to state-of-the-art measuring setups. ---------- You could setup a 5370B to measure the frequency of a typical low cost oscillator package. Step one is to show that it doesn't quite match the number printed on the can. Step two is to put your thumb on the can to change the temperature a bit and watch the frequency change. It would be fun to put a knob on the power supply voltage so you can see that change too. That probably needs a voltmeter. ------- Maybe you should keep a clipboard on the wall so you can add a note describing why you used a piece of gear each time you turn it on. Better would be when you turn it off. Then you know what you really used it for rather than what you thought you were going to use it for and/or if it did what you wanted it to do. ---------- I started working at Xerox late in 1976. Shortly after I got there, Ed Taft released a new version of the Alto OS that significantly improved timekeeping. The machine was designed with a 170ns cycle time. Crystals come in MHz rather than ns so they were built with 5.88 MHz oscillator packages. That's 170.068 ns, off by 400 ppm. The initial software used 170 ns. The fix was a minor tweak to that constant. -- These are my opinions. I hate spam. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
