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Discussion of Problem 1704. DemodulationandreyDagger`~ About Noise() // Problem 1704. Demodulation 27 Dec 2024 03:35 Looks like Noise function acts like in real world. It is some random variable from normal distribution with zero expected value, and some small variation Edited by author 27.12.2024 03:35 B@R5uk This is soo000ooo funny problem! // Problem 1704. Demodulation 13 Jan 2018 21:30 You need to compute two scalar products, each for 0 bit and 1 bit. Then just compare it. That'a ALL!!! If you are afraid of amplitude being negative then abs() each product and compare them after. There is no need to fuss about anything: carriers and constant level orthogonal to each other and noise guaranteed to be small by problem statement. Well, if noise was too big betrayer would never be able to transmit his data. Even if every bit was transmitted with differen amplitude and different constant level this approach still would work. I just do not undestand why this problem is rated soooooo high?! xurshid_n What kind of Noise() function??? // Problem 1704. Demodulation 21 Jan 2017 11:29 Noise() - is constant, or linear, trigonometric, or random function??? Fyodor Menshikov Hints [5] // Problem 1704. Demodulation 21 Apr 2009 21:30 1. Minimize sum of squares of differences, not sum of absolute values of differences. 2. It is important, that constant AMP (amplitude) is the same for all bits. 3. There is no test with negative amplitude. svr Re: Hints [1] // Problem 1704. Demodulation 28 Oct 2009 17:35 Hint should be: notion of appropriate statistical processing: extracting a and b in a+b*k from noise Or MNK Or sequental analysis Or maching learning Or optimal decision theory What artical in Wikpedia should read? Pavel Atnashev Re: Hints // Problem 1704. Demodulation 10 Nov 2009 12:39 Start with this one: http://en.wikipedia.org/wiki/Frequency-shift_keying Alipov Vyacheslav [Tomsk PU] Re: Hints [2] // Problem 1704. Demodulation 22 Jul 2010 01:48 Would you be so kind to give the slightly more detailed description of your solution? I tried to used DFT but it seems to be too sensitive to noise. I heard of Arctan-Differentiated Demodulator, but I can't find the literature on this theme. Does anybody know, is it applicable here? Vedernikoff Sergey (HSE: АОП) Re: Hints [1] // Problem 1704. Demodulation 23 Jul 2010 02:29 Use OLS (ordinary least squares) estimator for this problem Alipov Vyacheslav [Tomsk PU] Re: Hints // Problem 1704. Demodulation 23 Jul 2010 19:55 Thanks a lot. I've never used this method before. But it's worth keeping in mind :) SirJ [KhAI] Smusenok Sergey WA3 Please help!!! // Problem 1704. Demodulation 9 Jan 2010 00:28 я решаю через количество пересечений графиком синуса ось ох, вроде алгоритм правильный а преодолеть третий тест не могу. помогите пожалуйста!!! OpenGL Mistake in statement [2] // Problem 1704. Demodulation 10 Apr 2009 13:03 In russian, "кочевники ограбили очередной корован". Right word- "караван". Sandro (USU) Re: Mistake in statement [1] // Problem 1704. Demodulation 10 Apr 2009 13:12 OpenGL :) // Problem 1704. Demodulation 10 Apr 2009 13:49 Blue Mary What does "punctuation signs" mean? // Problem 1704. Demodulation 4 Apr 2009 16:23 All printable nonspace & non-letter characters?
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