Hedy Lamarr And Wi-Fi: On Cnn!

[vetuste_ennemi]

CNN's courageous (i.e. totally conventional) reporter Christiane Amanpour (didn't you love her on Brexit night?) discussing a real woman.

Fans of the Listener will know Ms Lamarr because she was a theme two or three years ago. Can't remember the title.

[vetuste_ennemi]

Trigger warning to Labour supporters: Ms Lamarr was Jewish.

[Buenchico]

I struggled to make sense of your post but this seems to explain at least some of it:
https://www.theguardian.com/film/2018/mar/08/hedy-lamarr-1940s-bombshell-helped-invent-wifi-missile

[vetuste_ennemi]

//I struggled to make sense of your post//

I'm surprised, Buenchico.

Amanpour's now on more familiar territory: interviewing Annie Lennox on female empowerment, the #MeToo movement, Donald Trump, *** walks, Pussy marches and why importing rapists into Europe is a good idea.

PS: I made up the last clause.

[vetuste_ennemi]

...don't think Christiane or Annie are that bothered.

[1ozzy]

This is very scientific, tad too scientific for me.

Jim360 may be able to shed some light on the subject.

[vetuste_ennemi]

Jim will understand the physics of frequency hopping (don't ask me, Ozzie), and will remember the crossword (it beat me, although I did manage the Turing machine one).

[Garaman]

The Listener was called German Serial Composition. The setter was Quinaplus, who had given us some brilliant crossword tools.

Lamarr’s patent was for a very basic system that used a mechanical device both the transmitter and at the receiver in the missile to switch frequencies. The two devices had to be synchronised manually before launch. The top figure shows the transmitter with the device at the bottom rhs selecting a channel, which would select a certain tuned circuit for the variable frequency oscillator, therefore selecting the transmission frequency. The two oscillators at the top of the diagram modify the amplitude of the transmitted signal. So if you want to move the missile left you would modulate the amplitude with a 100hz signal and if you wanted to move it right you would modulate it with a 500hz signal. The receiver does just the reverse. Its mechanical device has selected the same signal so it is on the correct frequency. The detectors pick up the modulation on the received signal which is then filtered and rectified to a DC voltage so that the 100hz or 500hz modulation could be used to turn a motor and alter the direction of the missile left or right.

These days frequency shift tends to be used only where both ends have a transmitter and receiver so that synchronisation information can be passed from one to the other, without the need for any prearranged synchronisation. They basically tell each other where to go next.

[jim360]

Nice to get name-checked for two very different reasons! Although I'll defer to Garaman's answer since I'd have to read up (again) on Hedy Lamarr's work. Do indeed remember the Listener. Pretty sure that was the same year as Quinapalus' other one, ELM, which also had a mathematical theme.

[vetuste_ennemi]

Thanks for your explanation, Garaman.