October 15, 2002

3:31 AM

In 1924 George Antheil caused a riot with his ballet score for 'percussion orchestra, two pianists, seven electric bells, 3 airplane propellors, a siren, and 16 synchronized player pianos'. In 1933, Hedy Lamarr caused a sensation by appearing nude on film. In 1942, Antheil and Lamarr jointly filed a patent for a secret communications system, having thought up 'an interesting scheme to control armed torpedoes over long distances without the enemy detecting them or jamming their transmissions' over dinner.
posted by misteraitch (12 comments total)

This technique is also called Frequency Division Multiplexing (informaly "frequency hopping") and is the underlying concept on which all GSM cellular networks (and some other systems) are based on.
posted by PenDevil at 4:10 AM on October 15, 2002

i'm confused. fdm (at least as i understand it after scanning here) broadcasts simultaneously on different channels, while the patented system always transmits on a single frequency. the frequency itself, in the patent, carries no information, but in fdm you must know the frequency of any channel to make use of the data.

in other words, as far as i can tell, the only connection the patent has with fdm is that (1) it uses radio waves and (2) more than one frequency is used (and that's true of any modulated signal anyway!). have i missed something, or is this an example of a nice story and a desire to popularise science pushing people to see connections that, in practice, are rather tenuous?

maybe it seems like i'm splitting hairs, but i could see no appreciation at all of the very clever engineering behind ofdm in that patent. the connection is at a similar level to that between a tuning fork and modern chromatic tuner (if you're not a musician - you can buy a little box of electronics, the size of a cigarette packet, that has a microphone; you put it near you instrument, play a note, and it decides what note you were trying to play and tells you if you were sharp or flat). but even that's not a good comparison, because inventing a tuning fork is more comparable to inventing radio than what is described in this patent. you might say (pushing an already obscure comparison way too far) that the patent is equivalent to the suggestion that one buy a set of tuning forks, one for each note...
posted by andrew cooke at 4:59 AM on October 15, 2002

Perhaps PenDevil is confusing different cellular systems. CDMA, not GSM, is based on spread-spectrum communications.
posted by gyc at 6:18 AM on October 15, 2002

Whoops! Seems my 3rd year networks lectures have decided to depart me.

Lamarr and Antheil came up with Code Division Multiplexing. *smacks forehead*

Although GSM is based on FDMA (and a bit of TDMA) the current trend for newer generations of netowrks is towards CDMA like technologies.
posted by PenDevil at 6:21 AM on October 15, 2002

And here I was hoping this involved some system of remote control using nude actresses and a couple of pianists with propellers.

(Good post, btw. This little tidbit about Hedy Lamarr is trotted out every now and again)
posted by briank at 6:31 AM on October 15, 2002

Wired Magazine once ran a great article on George Antheil. The article mentions the Antheil-Lamarr colaboration in a paragraph.

One question also rises: was Hedy Lamarr the smartest sex symbol ever? :)
posted by falameufilho at 6:40 AM on October 15, 2002

Fascinating. This story ties together an old science lecture from high school and reoccurring questions about Mel Brooks movies.

The story also got mentioned in an old Alfred Hitchcock magazine in the late 80s.
posted by Tystnaden at 6:44 AM on October 15, 2002

Although on looking at this page it seems frequency hopping is used as well in spread spectrum encoding as well. I incorrectly stated that GSM is based on FDMA when in fact it's Frequency Hopping Multiplexing Access (FHMA). So in fact GSM is related to some spread spectrum techniques. That's two black marks against me now. Apologies for the confusion.
posted by PenDevil at 6:53 AM on October 15, 2002

So how are these three things related? Is this an "on this day in history" post?

If you think '33 was early for film nudity, you definitely have to check out Cinema Europe: The Other Hollywood.
posted by hyperizer at 7:39 AM on October 15, 2002

Nice rack!
posted by wackybrit at 8:32 AM on October 15, 2002

That's Hedley!
posted by mr_crash_davis at 9:07 AM on October 15, 2002

I caught the American Composers Orchestra's performance of Antheil's "Ballet Mecanique" at Carnegie Hall a couple of years ago, and it was quite an experience.
posted by Songdog at 12:47 PM on October 15, 2002