First time I saw this, it was a power-on reset circuit. RC from the supply, emitter follower, schmitt trigger TTL gate. It oscillated so hard it never pulled the gate input up. Looked like a pretty good 100 MHz sine wave. We added a 39 ohm gate resistor, because I always liked the color codes on a 39 ohm resistor.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
That is a feature, it's called VHF-Thevenin :-)
This can also happen when people place 74AUP and similar logic but use
70's style layout techniques with two-layer and GND islands.-- Regards, Joerg http://www.analogconsultants.com/
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