DAY 120: Air data

February 8th, 2015 § 0 comments

One of the interesting questions you can ask if you have too much time on your hands is this – to go back to texting (remember?): Here’s my text, in my phone; it reads something like ’01001000 01101111 01110111 00100000 01100001 01110010 01100101 00100000 01111001 01101111 01110101 00111111 00100000 01011000′, meaning of course ‘How are you? X’. So it’s a string of 0′s and 1′s’ and  you press ‘Send’. It now goes up in the air. So what then?

Ask around the internet the simple question ‘Can you send digital data through the air?’ There are two answers to this, yes and no – and, the internet being what it is, you’ll find both. To me it’s obvious that, in the air, you have to have waves, not 1′s and 0′s. (A simple point I’ve seen somewhere is that the air can’t tell whether you’re sending a 0 or not sending anything at all. It was put more technically where I saw it of course.) And so you have to convert the digital data to 200px-PAL_colour_bar_signal_measured_vector_edit.svganalog, send them as waves from one mobile tower to another, down to your friend’s phone (analog still, surely), and then convert it back into a digital signal or string of 1′s and 0′s which your friend’s phone can read. This is of course simply a question of modulation; the vector x = (x1,…,xn) of 1′s and 0′s is replaced by a wave function x(t); I suggest you refer to the picture which shows a collection of binary ‘vectors’ arranged around a circle. Such a pattern seems to go by the name of a ‘constellation’, and it explains – if that’s the word – the recipe you use for modulation.

[You're probably beginning to lose attention by this point, as people always do when I bring in e.g. Fourier series. Have you thought at all, to change the subject for a moment, about the theme of redemption, as evidenced in Tolstoy's late novel Resurrection? And how an original transgression (Shoah, Nakba) and a redemptive suffering might transform the conflict in Israel/Palestine, unifying two peoples in one messianic moment à la Benjamin? See Judith Butler as usual (Parting Ways), and see Az Theatre's BREATHING_SPACEwebstunning stage adaptation of the Tolstoy which played in Shoreditch in January. Other readers have been pointing out to me that the theme of redemption is treated with more zing and modernity in recent texts like Almodóvar's All About My Mother, and with more depth in most of Toni Morrison's oeuvre,all_about_my_mother_4_almodovar-300x168even if we pass up the questionable Stephen King/Darabont Shawshank version. Has anyone seen Hiroshima mon Amour lately? Or have they read Israeli rights organization B'Tselem's recent report on last year's war?]

Obviously these waves – remember them? – arrive at a remote mast, say in Tottenham, where your friend’s phone is situated; and travel down to her phone. There they have to be demodulated, or transformed into a sequence of 0′s and 1′s again. It’s basic Fourier analysis that modulation followed by demodulation gets you (nearly) back where you started, so that with any luck your friend will get exactly the message you sent. (‘How are you? X’) The transmission process will have been filtering out the noise so as to get something which translates sensibly, etc.

I quote a source on the always reliable ‘Stackexchange’:

(It also needs to be noted that, from the standpoint of ‘Information theory’ the maximum amount of information that can be encoded into a signal occupying a given bandwidth is essentially the same, regardless of whether it’s digital or analog, or how it may be multiplexed. why-would-you-do-that-it-makes-my-head-hurtHowever, while one could spend days discussing information theory and entropy I won’t go into it further, because it’s for the theoreticians, and because it makes my head hurt to think about it.) That’s enough of that; back another time.

Pythagoras

My friend Jan Bruegel the elder (or it may be the younger, the Bruegels like the policemen keep getting younger these days) sent me a picture:

01659f66-82b2-11df-acc7-002185ce6064_23He might have enlarged it; the diagram is obviously Pythagoras’ theorem; but what are all the weird calculations beside it? He can’t remember, he was probably stoned when he painted it; and now the picture is in the Prado, and it’s hard to get close enough to make any sense of it all. Using a magnifying glass, I seem to have made out some sums which I’ll (mostly) spare you – like:Screen shot 2015-02-08 at 20.07.01

(Being in a sort of feet-inch system, your numbers seem to be duodecimals, but that’s not my fault.) 34 is 52+32 if that helps. It makes it sort of Pythagorean – but what then? I’m off to the Prado.

At the Movies

To ‘Selma’, a sellout with many plaudits but no awards so far except for the song ‘Glory‘ featuring Common and John Legend. Naturally I looked for a party-line review, but a google search on ‘Morning Star Selma’ took me, not to the people’s newspaper, but to the

8971_590213671106532_7131455133915494125_nMorning Star Baptist Church

in Selma. That, as they say, is serendipity.

A propos, John Lewis, the longtime Georgia congressman who is portrayed as a hero in the  film and known as the “conscience of the U.S. Congress,” said last night that he won’t attend Israeli Prime Minister Benjamin Netanyahu’s scheduled speech to Congress in March – encouraging, but not surprising.

Poetry

Having paid tribute to Common (above), I looked around for poems about demodulation. Nary a one, I kept finding that ‘this page (poems about demodulation) is experiencing problems.’ No shit! A word with so many rhymes?

Waves travel thru the air to meet demodulation

Each little one an unceasing vibration

As the sinner’s soul faces its fate of damnation

They split into bits like the spots on a dalmatian

It’s serious stuff not just a flirtation

Down in the bar with a Haitian-Croatian

Can’t write any more for my hope of salvation

I’m tellin’ you it’s time for recalculation

It’s time for we all to demand liberation.

No more castration, no masturbation.

Cause them’s the roots of our communication.

(About fifty lines more, but I’ll pause there.)

Music

I’ve given you ‘Glory’; but among the works of Almodóvar, mentioned above, the blog has also been exposed to the less redemptive ‘Women on the Verge of a Nervous Breakdown’; which gives us an excuse to play ‘Soy infeliz‘.

 

Leave a Reply

What's this?

You are currently reading DAY 120: Air data at Luke Hodgkin.

meta