This is a photograph of the screen of an antique oscilloscope in a local radio museum. What you are seeing are sound waves measured during an old Johnny Cash song coming through an antique radio. The screen of the machine is a thick plastic so this is as sharp as it actually is.

Somehow I missed the part of the criteria that these were 'technology images for selling tech". I apologize that my submission doesn't really fit the theme. If I could figure out how to delete it i would! :o)