On Dec 22, 8:52*am, "William Sommerwerck"
wrote:
Also, those Japanese VCR manufacturers all paid licensing fees to
Ampex. They shrunk and repackaged the concept. Does that qualify
as an invention?
Yes, because the Japanese helical-scan system (invented by Hitachi,
I think) was quite different from the Ampex quadruplex [sic] system.
Helical scan tape recording was invented by RCA's Earl Masterson in
1950 (2,773,120). A good picture of the alpha wrap is shown in DC
resident Arthur W. Holt's patent 2919314, "Means for recording and/or
reproducing recorded high frequency signals," applied for in 1956. As
usual for that era, the Japanese merely copied and adapted American
inventions.

Fascinating.

What's interesting about this patent is that the head moves in a circle,
while the /tape/ moves in a helix. This is "backwards" to the way modern
helical-scan systems work.

While Masterson's claims are drawn quite narrowly, Holt's first claim
covers the "modern helical-scan system" of which you speak.