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I designed and built the Pyramid Generator (PG) to be a durable,
portable, well constructed device that would pass the test of time. I
personally detest cheap made items in flimsy plastic boxes that seem to
fall apart if you drop them or happen to set a hot soldering iron on
them. So, I opted for a more expensive die cast aluminum box with
bright blue epoxy paint front silk screen legends that have proved to be
very durable. And, I must applaud forum member Fred (PA4TIM) for his
acute observation that I used a 75 Ohm chassis mounted BNC connector and
labeled it 50 Ohms. The reason is that a 50 Ohm cable terminated in a
50 Ohm connector will fit a 75 Ohm chassis mount connector but not
visa-verse. If you are at an electronic swap meet and have the wrong
cable, are just plain out of luck if you are wanting to test a possible
purchase. The second reason is that the small impedance mismatch at the
low frequencies employed in the PR caused no appreciable
discontinuities. But, I must disagree with Fred when he says that it is
not imperative that the pyramid steps be time correlated to the
display. The PG uses a crystal controlled oscillator and is designed to
display any non-linearities that might be apparent in a trace, Merely
having the beginning and end of a trace fall on the correct vertical
graticule lines says little about the trace linearity over the full 10
DIV display.

Reed Dickinson