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How Hollywood's Hedy Helped Heighten Handhelds (hackaday.com)
szczys writes: Hedy Lamarr is a household name for the wrong reason. Her name is known as a Hollywood actress, but her legacy is in your pocket and reaches far more people than her movies. She was a brilliant thinker who plied her skills during World War II, developing technology that could help to win the war. Her patent wasn't used at the time, but is a foundation of spread-spectrum which is used in the radio modules of your cellphone: WiFi, Bluetooth, GPS, and others. This frequency hopping concept sat unused for decades before being added to the most ubiquitous of wireless connectivity methods.
No, it's Hedley!
“He’s not deformed, he’s just drunk!”
Asinine Alliteration Accentuates Author's Atrociously Antiquated Awareness About Awesome And Able Actress
Obliteracy: Words with explosions
But how can we encourage more women and minorities to join STEM fields? We're discouraging future Hedy Lamarrs with the toxic 'bro culture' that pervades programming.
I think it was encumbered not by the fact that it was patented, but (per TFA) by the fact that it was classified.
If it weren't for deadlines, nothing would be late.
This frequency hopping concept sat unused for decades before being added to the most ubiquitous of wireless connectivity methods.
Frequency hopping has been used by the military long before cell phones were invented.
Hedy Lamarr helped win the Cold War.
Heavy "H" Heaping Hinders Helpful Headlines. Have Heart!
Table-ized A.I.
The invention was quite interesting, too -- a mechanical implementation of spread spectrum that was based on player piano technology.
The patent expired in 1958.
Exactly, (though that came after the war)... And some things, like truly effective encryption (if it exists at all) is born secret
“He’s not deformed, he’s just drunk!”
Lamarr invented "frequency hopping" while CDMA cellular and GPS use "direct sequence". Frequency hopping is just what it sounds like: a narrowband transmitter is continually retuned to a different radio channel. Unless the receiver tuning follows the same sequence at the proper times it cannot receive the transmission.
Direct sequence XORs a narrowband signal with a high speed pseudorandom "chip" sequence, and the receiver undoes this operation by XORing it again by the same sequence properly synchronized in time. It closely resembles a keystream-type encryption system, though the "keystream" is not necessarily secret. The main difference is that direct sequence is a wideband signal while, at any instant, a frequency hopped signal is still narrowband.
Each method has advantages. Frequency hopping can be especially resistant to strong narrowband jamming, so it's a favorite of military systems (Lamarr's intended use). Direct sequence is easier to use with coherent modulation so it tends to use transmitter power more efficiently, and it can often provide precise timing and positioning as a side benefit. Or, in the case of GPS, as its primary purpose.
While CDMA mobile phones were very important in the 1990s and 2000s, it is now being replaced with LTE (Long Term Evolution), which uses OFDM - Orthogonal Frequency Division Multiplexing. So do many other modern terrestrial digital communication systems including DSL, HD Radio, DVB-T (but not ATSC), WiFi and DRM (Digital Radio Mondiale).
Many applications of frequency-hopping spread spectrum require complexity that isn't practical with vacuum tubes. Commercial applications needed to wait for integrated circuits.
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This story comes up a lot. I always assumed it was common knowledge amongst engineers. But not as many engineers on slashdot anymore.
Here is a photo of Hedy Lamarr. Naked.
https://jnpickens.files.wordpr...
Here is a photo of Phil Zimmerman. Fully clothed.
http://cdn.androidbeat.com/wp-...
Now who wants to argue that there shouldn't be more women in tech?
You are welcome on my lawn.
You know - none of that matters if you publish prior to getting informed what you just published is "classified". Oops, cat is out of the bag, barn, and farm.... Kind of like Phil....
The cesspool just got a check and balance.
Who is Hedy?
They developed the system for the war effort originally. Thus the secret classification.
this seems to come up on tech sites yearly. how very forgotten..
world was created 5 seconds before this post as it is.
Don't you mean: Alliterations are awfully asinine?
Depends.
Hedy Lamarr's spread spectrum, called Frequency Hopping Spread Spectrum (FHSS) is used in Bluetooth and early WiFi (802.11, no "b") is the first known implementation. Basically, Hedy based it on a piano roll used by player pianos in order for the Navy to control torpedoes without them being jammed.
The other form of spread spectrum, Direct Sequence Spread Spectrum (DSSS) is much more modern - its patents are owned by our dear friend Qualcomm, who used it to create CDMA as an alternative to FDMA and TDMA mechanisms.
Qualcomm owns DSSS because they basically invented it, and they're quite recent.
FHSS is still spread spectrum, and it still accomplishes the goal of spreading the signal out and interference on a channel only affects the signal for a little while.
FHSS is easier to do if your communications are channelized and you can switch between channels easily (which is why it's older). DSSS requires more computation and initial acquisition of the stream is a lot harder since you're not entirely sure where in the chip code you are so you not only have to pick the right PRNG seed, but you need to advance the code until your correllator starts detecting a signal.
(The chip codes are carefully selected so the correllator only produces a noise output if the chip code is wrong).
Not really since the patent was based on a working prototype. Commercial applications had to wait for desperation driving a search for a solution to potentially congested airwaves. See also the current "cable tv" appliances that have IPv6 addresses only due to a rollout larger than the remaining unallocated continuous IPv4 address space.
At least, it looks like that
Windows 2000 - from the guys who brought us edlin
I'm aware of what they did and why. What my statement was is that if you, as an individual, publish something like Phil Zimmerman did with PGP (which was subject to these types of laws) then you have effectively neutralized these types of laws if that is your intent. Some will say this is bad, or even illegal. Phil was subjected to some intense scrutiny and an investigation, but ultimately was effectively "just" harassed as no legal action was taken. Much like DVD Jon, or any of the others were attempted to be harassed into silence most likely as warnings to others in the future. However, it appears that freedom of speech still reigns supreme, however much some try to chill it.
The cesspool just got a check and balance.
Now we'll see two or three times the volume of this tidbit on Reddit /r/todayILearned.
Also, it was classified for a few years during and after the war.
So... she's known for being an actress, a very public field, more than she's known for something that she was sworn to secrecy for,. This is a problem, or even a surprise, why?
That seems to about cover it.
If I recall, the prototypes involved mechanical devices that were kept in sync with clockwork. Useful for shorter time periods like controlling a torpedo, but not all that useful for something needing long term stability.
I'm not sure what your point is since the patent dates to less than ten years before solid state transistors were commercially available.