zeeglen

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CC&BW

Glen Chenier has spent most of his engineering career in the communications field with such companies as Fujitsu, Fitel Photomatrix, and Gandalf Data. He has also developed small-motor electronic drive systems for the hobby market. From his new home in Allen, Texas, he now spends time working on EDN projects and reverse-engineering legacy telecom systems to facilitate continuing support, while pondering the nuances of analog circuit test and the many lessons he has learned.


zeeglen

's contributions
  • 12.03.2015
  • 25 gifts for engineers under $25
  • David, you might have the same type I have. They were incredibly inexpensive, probably because they eat batteries when turned off. I just remove the battery until next time I need to use them.
  • 11.25.2015
  • Do you know your colour codes?
  • Nice idea. I like to color code wires on schematics the same way, but because of the white background have to make 8 = dark grey, 9 = light grey. A disappointment with a recently acquired MSO is the logic analyzer probe pod. Obviously assigned by a digital type... The colors on the label are: Gnd Grey 0 White 1 Red 2 Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 Brown So now I will be totally confused when using this.
  • 12.03.2016
  • 1st text message is sent, December 3, 1992
  • Does Morse code count as texting? Back when I was young and foolish I strapped a code key to my thigh and had QSOs while driving a 4-on-the-floor stick shift. (Yeah, I know, pretty stupid, but I was a teenager.) Maybe I am the first person in history to text-while-driving. Hmmm...I should contact the Guinness book of world records...
  • 12.03.2016
  • 1st text message is sent, December 3, 1992
  • Exactly. Whenever my wife gets on my case about "not learning new technology" by having a smartphone, I tell her I was texting 40 years ago via shortwave radio and the novelty has worn off.
  • 12.03.2015
  • Whither logic analyzers?
  • I recently (after much B&C) got the boss to buy me a Rigol MSO with 16 LA channels and 4 analog channels. An upcoming project is to map out all the mechanical relay and silicon switching functions that take place during a 90-second-long self-test routine of a DUT. The main time base will be the test pattern at the input of a A to D converter, so the analog channels are absolutely necessary.
  • 12.17.2013
  • PCB signal coupling can be a problem
  • Used multiple broadside-coupled differential striplines closely spaced so that 2 pairs could run through the 1mm space between connector pins on a multi-slot backplane. The stray capacitance between them was mostly common mode so crosstalk was rejected in the differential receivers. Worked extremely well, testing showed far more crosstalk in the slot connectors than in the stripline runs.