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Handhelds Technology

How Hollywood's Hedy Helped Heighten Handhelds (hackaday.com) 67

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.
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How Hollywood's Hedy Helped Heighten Handhelds

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  • by fustakrakich ( 1673220 ) on Monday November 16, 2015 @08:39PM (#50944303) Journal

    No, it's Hedley!

  • Agh (Score:5, Funny)

    by American AC in Paris ( 230456 ) on Monday November 16, 2015 @08:45PM (#50944341) Homepage
    Asinine Alliteration Accentuates Author's Atrociously Antiquated Awareness About Awesome And Able Actress
  • by Anonymous Coward

    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.

  • by Anonymous Coward

    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!

  • by binarstu ( 720435 ) on Monday November 16, 2015 @09:21PM (#50944533)

    The invention was quite interesting, too -- a mechanical implementation of spread spectrum that was based on player piano technology [harvard.edu].

  • It's a great story, but her invention was never used. It's really a huge stretch it really relates at all to current spread-spectrum technology. Even if you think it is related, spread-spectrum as developed did not base their ideas on her invention, and it's unlikely they were even aware of it.

    • by tlhIngan ( 30335 )

      It's a great story, but her invention was never used. It's really a huge stretch it really relates at all to current spread-spectrum technology. Even if you think it is related, spread-spectrum as developed did not base their ideas on her invention, and it's unlikely they were even aware of it.

      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 u

  • by Phil Karn ( 14620 ) <karnNO@SPAMka9q.net> on Monday November 16, 2015 @09:54PM (#50944717) Homepage
    I don't mean to denigrate her contribution in any way, but Lamarr's frequency-hopping spread spectrum is not the one used in CDMA mobile phones. It is used in Bluetooth.

    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).

    • Thank you! Every time this comes up, I end up writing a rebuttal along the same lines.

  • Here is a photo of Hedy Lamarr. Naked.

    https://jnpickens.files.wordpr... [wordpress.com]

    Here is a photo of Phil Zimmerman. Fully clothed.

    http://cdn.androidbeat.com/wp-... [androidbeat.com]

    Now who wants to argue that there shouldn't be more women in tech?

    • by Anonymous Coward

      Hard to believe more women don't choose STEM careers, when they could work with guys like you.

  • by dohzer ( 867770 )

    Who is Hedy?

  • At least, it looks like that
  • Now we'll see two or three times the volume of this tidbit on Reddit /r/todayILearned.

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