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Oona Räisänen (windytan)
Lives in Helsinki
6,167 followers|10,587,666 views
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The mathematics and properties of discrete signals and quantum mechanics have intriguing parallels. Take, for instance, Heisenberg uncertainty principle in QM and Gabor(-Heisenberg) limit in signal processing. Or the fact that the quantum state of an isolated system is a complex-valued wave function; and that the position and momentum of a particle are related through a Fourier transform.
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Peter Barrett's profile photoEmanuele Ziglioli's profile photoROBIN Guillaume's profile photo
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+Emanuele Ziglioli I understand, I did not want to be mean. The similarities are often bad friends, but not always.
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Trackers and bank accounts
A Finnish online bank used to include a third-party tracking script in all of its pages. Ospi first wrote about it (in Finnish) in February 2015, and this caused a bit of a fuss. The bank responded to users' worries by claiming that all information is colle...
A Finnish online bank used to include a third-party tracking script in all of its pages. Ospi first wrote about it (in Finnish) in February 2015, and this caused a bit of a fuss. The bank responded to users' worries by claimi...
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I've always been INTP, but now I'm getting INFP. (Emotion chip?)
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Erika Berkenhof's profile photoTomáš Mládek's profile photoNoah Friedman's profile photoJussi Lahtinen's profile photo
6 comments
 
+Tomáš Mládek Only if you can't speak...
 or write, but then you probably wouldn't able to do the test either.
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Mike Rooke's profile photoChristopher Hewitt's profile photoAntti Kivivalli's profile photoHakan Kocaman's profile photo
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Almost 25 years ago I attended a seminar on magnetic stimulation of the cortex. That time the gadgets were new and the US models came with instructions to use hearing protector while using it on a patient...

The huge electric pulse in a coil caused only a small snap because of the manufacturers warnings a Finnish doctor had prepared a paper after measuring the sound a magnetic stimulation coil could produce. He used a normal dynamic microphone in his measurements...

https://youtu.be/B_olmdAQx5s
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I wrote a little RDS decoder for RTL-SDR (Linux/OSX).
I originally wrote redsea as a script to decode RDS from demultiplexed FM stereo sound. Later I've experimented with other ways to read the bits, and the latest addition is to support the RTL-SDR television receiver via the r...
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Mika Hämäläinen's profile photoMartin Kock's profile photoJeffrey Guevin's profile photoBrendon H.'s profile photo
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Okay, the video makes a lot more sense viewed on a tablet. My phone screen didn't really show the full drama.
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Have her in circles
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Building a half-wave dipole. What's the effect of the air gap (feed gap)? How wide should it be in relation to the elements? Does it matter?
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Marcelo Bornscheuer (XQ6BQ)'s profile photoWVØH Myron's profile photoOona Räisänen (windytan)'s profile photoBrian Morrison's profile photo
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Feel free to ask about baluns if you want to ☺
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What kind of filter would you use to bandpass the signal centered at +50 kHz?
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Daniel Yount's profile photoColby Boyer's profile photoAndy Sloane's profile photoOona Räisänen (windytan)'s profile photo
8 comments
 
Thanks for the help, I solved this.
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Wanted: recordings of C64 (or similar) data cassettes for testing my new decoder. Any format will do, preferably not very compressed. Damaged and unreadable tapes preferred.
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Andreas Höfler's profile photoFlorian Loitsch's profile photoDominik Klein's profile photoDec Kelly's profile photo
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I might have some tapes still, but honestly I no clue as to where they might be. The same goes for my ZX81...
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Improved redsea quite a bit during the weekend. More resistant to low SNR. Also more infodump in the blog post.
redsea is a command-line RDS decoder. I originally wrote it as a script to decode RDS from demultiplexed FM stereo sound. Later I've experimented with other ways to read the bits, and the latest addition is to support the RTL...
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Dec Kelly's profile photoEkki Plicht's profile photoStefan Marx's profile photoMichael Ball's profile photo
2 comments
 
Pirate FM stations tend to have more interesting RDS text than legal/regulated broadcasters.
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Receiving RDS with the RTL-SDR
I originally wrote redsea as a script to decode RDS from demultiplexed FM stereo sound . Later I've experimented with other ways to read the bits, and the latest addition is to support the RTL-SDR television receiver via the rtl_fm tool. The DSP side of my ...
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Robert Greenwalt's profile photoSebastian Schmidt's profile photoOona Räisänen (windytan)'s profile photoDavid Lundberg's profile photo
6 comments
 
Worked more or less straight away on Linux. No warning on missing sox, but minor thing. :)
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Made a dedicated Posters subpage.
Sometimes I make posters of a technical nature. The sound of the dialup, pictured This poster is a second-by-second decomposition of the legendary beeps and boops that were once the sound of the Internet. High-res prints can ...
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Erik Pusch's profile photoComputeum's profile photoMizsei Zoltán's profile photoCiorceri Sorin's profile photo
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I have this one, will wait for the improved Tape Hiss Poster.  Great work, Oona.
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People
Have her in circles
6,167 people
The Mobile Music School's profile photo
Артем Дробанов's profile photo
Luis Salgado's profile photo
Emon Rabya's profile photo
Yngve Grön's profile photo
Scott Stickeler's profile photo
Soumana MAIGA's profile photo
Dave Burgess's profile photo
Manish A.Shetty's profile photo
Communities
5 communities
Basic Information
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Female
Story
Tagline
Signals & electronics hacker.
Introduction

A self-taught signals hacker from Helsinki, Finland. CCC and 44CON speaker. Studies computers. Fond of electronics, mysteries, codes and ciphers, and vintage tech.

Absorptions is a blog about my hobbies.

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Currently
Helsinki