Там человек пишет цветное видео 100x75 (причём с черезстрочной развёрткой) на 2 аудиоканала (один канал яркость, второй канал - цвет) с помощью питона и потом играет его джаваскриптом:
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И сразу вспомнились мои потуги середины 80х сделать запись видео на кассетный магнитофон с помощью диска нипкова
P.S. У нас тут тема поднималась несколько раз, но я решил создать новый топик т.к. именно про запись ВИДЕО (несколько кадров в секунду) на АУДИО кассету (с обычной скоростью на немодифицированный мафон) в прямую нигде не говорилось (хотя думалось):
А вот собственно о чём мне думалось сколько-то лет назад - во первых, видео должно влезать в один канал (хотя бы и чёрно-белое), чтобы аудиодорожка шла вторым каналом (ибо без звука неинтересно). Во-вторых, записывать точки яркости одну за другой бессмысленно, т.к. разрешение и частота кадров будут очень фиговые (см. выше). И в результате возникла у меня идея использовать разные частоты - спектр ведь может писаться целиком, передавая много информации в единицу времени. Можно строки видео гнать параллельно на разных частотах! Отталкиваясь от спектра прямоугольного сигнала (мы ведь будем работать с цифровыми генераторами):
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можно попытаться выбрать частоты, которые бы гармониками друг на друга не накладывались:
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Сделать снизу кадра - низкие частоты (скажем от 100 Гц - тогда при частоте кадров 12.5/сек у нас в одну строку теоретически влезет 8 периодов), сверху кадра - высокие (допустим до 16 кГц, чтобы оставаться в диапазоне нормальных аудиокассет) и также хотелось бы оставаться в рамках аппаратного кодирования и декодирования в аналоговой форме - без DSP
т.е. имея 3 частоты на октаву получаем 22 строки видео (правда восьмая строка попадает на пятую гармонику частоты первой строки, точнее строка N попадает на пятую гармонику строки N-8 - гармоники отложены по вертикали под каждым номером строки - 3я, 5я, 7я и 9я плюс-минус 10%)
Если разнести видеостроками на полоктавы, то тогда каждая строка N будет попадать в зону 3ей гармоники строки N-3 отступая всего на 6%, а гармоники 5,7 и 9 будут аккуратно обойдены:
А если взять 4 ноты на октаву, мы получим 30 видеострок (слегка залезши за пределы 16 кГц), но зато каждая будет попадать в зону всех гармоник предыдущих нот (с отступом порядка 6%):
Возможно если готовить видео программно, то можно и каждую ноту генерить чистыми синусоидами без гармоник (все 88), а аппаратный декодер (скажем на операционниках) будет выделять сигналы в своих расширенных диапазонах спектра и показывать меньшее количество строк...
P.S. Под спойлером более детальные цифры, подсчитанные с помощью программы, представленной в сообщениях ниже:
30
Code:
TRY 2^0.250000 (MUSICAL) 0: 110.000000 1: 130.812783 2: 155.563492 3: 184.997211 4: 220.000000 5: 261.625565 6: 311.126984 in 3rd with 0 (6%) 7: 369.994423 in 3rd with 1 (6%) 8: 440.000000 in 3rd with 2 (6%) 9: 523.251131 in 5th with 0 (5%) in 3rd with 3 (6%) 10: 622.253967 in 5th with 1 (5%) in 3rd with 4 (6%) 11: 739.988845 in 7th with 0 (4%) in 5th with 2 (5%) in 3rd with 5 (6%) 12: 880.000000 in 7th with 1 (4%) in 5th with 3 (5%) in 3rd with 6 (6%) 13: 1046.502261 in 9th with 0 (5%) in 7th with 2 (4%) in 5th with 4 (5%) in 3rd with 7 (6%) 14: 1244.507935 in 11th with 0 (2%) in 9th with 1 (5%) in 7th with 3 (4%) in 5th with 5 (5%) in 3rd with 8 (6%) 15: 1479.977691 in 11th with 1 (2%) in 9th with 2 (5%) in 7th with 4 (4%) in 5th with 6 (5%) in 3rd with 9 (6%) 16: 1760.000000 in 11th with 2 (2%) in 9th with 3 (5%) in 7th with 5 (4%) in 5th with 7 (5%) in 3rd with 10 (6%) 17: 2093.004522 in 11th with 3 (2%) in 9th with 4 (5%) in 7th with 6 (4%) in 5th with 8 (5%) in 3rd with 11 (6%) 18: 2489.015870 in 11th with 4 (2%) in 9th with 5 (5%) in 7th with 7 (4%) in 5th with 9 (5%) in 3rd with 12 (6%) 19: 2959.955382 in 11th with 5 (2%) in 9th with 6 (5%) in 7th with 8 (4%) in 5th with 10 (5%) in 3rd with 13 (6%) 20: 3520.000000 in 11th with 6 (2%) in 9th with 7 (5%) in 7th with 9 (4%) in 5th with 11 (5%) in 3rd with 14 (6%) 21: 4186.009045 in 11th with 7 (2%) in 9th with 8 (5%) in 7th with 10 (4%) in 5th with 12 (5%) in 3rd with 15 (6%) 22: 4978.031740 in 11th with 8 (2%) in 9th with 9 (5%) in 7th with 11 (4%) in 5th with 13 (5%) in 3rd with 16 (6%) 23: 5919.910763 in 11th with 9 (2%) in 9th with 10 (5%) in 7th with 12 (4%) in 5th with 14 (5%) in 3rd with 17 (6%) 24: 7040.000000 in 11th with 10 (2%) in 9th with 11 (5%) in 7th with 13 (4%) in 5th with 15 (5%) in 3rd with 18 (6%) 25: 8372.018090 in 11th with 11 (2%) in 9th with 12 (5%) in 7th with 14 (4%) in 5th with 16 (5%) in 3rd with 19 (6%) 26: 9956.063479 in 11th with 12 (2%) in 9th with 13 (5%) in 7th with 15 (4%) in 5th with 17 (5%) in 3rd with 20 (6%) 27: 11839.821527 in 11th with 13 (2%) in 9th with 14 (5%) in 7th with 16 (4%) in 5th with 18 (5%) in 3rd with 21 (6%) 28: 14080.000000 in 11th with 14 (2%) in 9th with 15 (5%) in 7th with 17 (4%) in 5th with 19 (5%) in 3rd with 22 (6%) 29: 16744.04 (ADDED)
Попробовал подвигать ноты чуток (после каждой пятой - дополнительный сдвиг), чтобы не попадало хотя бы на третью гармонику других нот (за пределами плюс-минус 10%), 3/5 попадают в 6% зону пятой гармоники и почти все попадают почти точно в седьмую и девятую гармоники других нот (что есть не очень хорошо):
Вообще чтобы не попадать ни в какие нечётные гармоники, надо просто брать по одной ноте из октавы (т.е. частота каждой строки отличается от предыдущей ровно в 2 раза):
А вообще можно совсем от нот отказаться - я набросал небольшую программку (если кому интересно - под спойлером), которая ищет самый подходящий набор частот, чтобы каждая частота не попадала в 10% окрестности нечётных гаромник 3,5,7,9 и 11 других частот (по возможности)
int main() { int i,j,l,p,lmax=0; double o,d,f,s,d1; double m = 2; double a[256]; double b = 0; for(s=0.03;s<1.001;s+=0.001) { printf("TRY 2^%lf\n",s); m = pow(2.0,s); f = 110.0; i = 0; l = 120; while(f<16000.0) { printf("%i: %lf\n",i,f); for(j=0;j<i;j++) { o = f/10; d = a[j]*3; if(f >= d-o && f <= d+o) { p = (int)(fabs(f-d)*100.0/f); printf(" in 3rd with %i (%i%%)\n",j,p); if(30+p < l) l = 30+p; } d = a[j]*5; if(f >= d-o && f <= d+o) { p = (int)(fabs(f-d)*100.0/f); printf(" in 5th with %i (%i%%)\n",j,p); if(50+p < l) l = 50+p; } d = a[j]*7; if(f >= d-o && f <= d+o) { p = (int)(fabs(f-d)*100.0/f); printf(" in 7th with %i (%i%%)\n",j,p); if(70+p < l) l = 70+p; } d = a[j]*9; if(f >= d-o && f <= d+o) { p = (int)(fabs(f-d)*100.0/f); printf(" in 9th with %i (%i%%)\n",j,p); if(90+p < l) l = 90+p; } d = a[j]*11; if(f >= d-o && f <= d+o) { p = (int)(fabs(f-d)*100.0/f); printf(" in 11th with %i (%i%%)\n",j,p); if(110+p < l) l = 110+p; } } a[i] = f; f *= m; i++; } if(l > lmax) { lmax = l; b = s; printf("BEST %lf (%i with %i lines)\n",b,l,j+1); } } }
и вот что она нашла
если устраивает попадание в окрестности 9й гармоники и больше, то можно получить 17 строк:
Code:
TRY 2^0.435000 0: 110.000000 1: 148.710192 2: 201.042919 3: 271.792100 4: 367.438685 5: 496.744338 6: 671.554052 7: 907.881198 in 9th with 0 (9%) 8: 1227.374426 in 11th with 0 (1%) in 9th with 1 (9%) 9: 1659.300783 in 11th with 1 (1%) in 9th with 2 (9%) 10: 2243.226704 in 11th with 2 (1%) in 9th with 3 (9%) 11: 3032.642482 in 11th with 3 (1%) in 9th with 4 (9%) 12: 4099.862224 in 11th with 4 (1%) in 9th with 5 (9%) 13: 5542.648155 in 11th with 5 (1%) in 9th with 6 (9%) 14: 7493.166084 in 11th with 6 (1%) in 9th with 7 (9%) 15: 10130.092403 in 11th with 7 (1%) in 9th with 8 (9%) 16: 13694.981660 in 11th with 8 (1%) in 9th with 9 (9%)
если 7я гармоника с отступом в 5% ок, то можно получить 20 строк:
Code:
TRY 2^0.361000 0: 110.000000 1: 141.274739 2: 181.441381 3: 233.028034 4: 299.281588 5: 384.372074 6: 493.655131 7: 634.009089 8: 814.267897 in 7th with 0 (5%) 9: 1045.777132 in 9th with 0 (5%) in 7th with 1 (5%) 10: 1343.108104 in 11th with 0 (9%) in 9th with 1 (5%) in 7th with 2 (5%) 11: 1724.974971 in 11th with 1 (9%) in 9th with 2 (5%) in 7th with 3 (5%) 12: 2215.412625 in 11th with 2 (9%) in 9th with 3 (5%) in 7th with 4 (5%) 13: 2845.289458 in 11th with 3 (9%) in 9th with 4 (5%) in 7th with 5 (5%) 14: 3654.250232 in 11th with 4 (9%) in 9th with 5 (5%) in 7th with 6 (5%) 15: 4693.211343 in 11th with 5 (9%) in 9th with 6 (5%) in 7th with 7 (5%) 16: 6027.565523 in 11th with 6 (9%) in 9th with 7 (5%) in 7th with 8 (5%) 17: 7741.297691 in 11th with 7 (9%) in 9th with 8 (5%) in 7th with 9 (5%) 18: 9942.271007 in 11th with 8 (9%) in 9th with 9 (5%) in 7th with 10 (5%) 19: 12769.015831 in 11th with 9 (9%) in 9th with 10 (5%) in 7th with 11 (5%)
а если подобраться к 3ей гармонике на 6% (расстояние между двумя соседними нотами), то можно получить 39 строк, правда при этому будут прямые попадания в 7ю и 9ю гармоники - см. под спойлер
39
Code:
TRY 2^0.187000 0: 110.000000 1: 125.223343 2: 142.553506 3: 162.282060 4: 184.740928 5: 210.307970 6: 239.413337 7: 272.546714 8: 310.265551 in 3rd with 0 (6%) 9: 353.204451 in 3rd with 0 (6%) in 3rd with 1 (6%) 10: 402.085838 in 3rd with 1 (6%) in 3rd with 2 (6%) 11: 457.732117 in 3rd with 2 (6%) in 3rd with 3 (6%) 12: 521.079509 in 5th with 0 (5%) in 3rd with 3 (6%) in 3rd with 4 (6%) 13: 593.193802 in 5th with 0 (7%) in 5th with 1 (5%) in 3rd with 4 (6%) in 3rd with 5 (6%) 14: 675.288282 in 5th with 1 (7%) in 5th with 2 (5%) in 3rd with 5 (6%) in 3rd with 6 (6%) 15: 768.744148 in 7th with 0 (0%) in 5th with 2 (7%) in 5th with 3 (5%) in 3rd with 6 (6%) in 3rd with 7 (6%) 16: 875.133748 in 7th with 1 (0%) in 5th with 3 (7%) in 5th with 4 (5%) in 3rd with 7 (6%) in 3rd with 8 (6%) 17: 996.247034 in 9th with 0 (0%) in 7th with 2 (0%) in 5th with 4 (7%) in 5th with 5 (5%) in 3rd with 8 (6%) in 3rd with 9 (6%) 18: 1134.121675 in 11th with 0 (6%) in 9th with 1 (0%) in 7th with 3 (0%) in 5th with 5 (7%) in 5th with 6 (5%) in 3rd with 9 (6%) in 3rd with 10 (6%) 19: 1291.077343 in 11th with 0 (6%) in 11th with 1 (6%) in 9th with 2 (0%) in 7th with 4 (0%) in 5th with 6 (7%) in 5th with 7 (5%) in 3rd with 10 (6%) in 3rd with 11 (6%) 20: 1469.754738 in 11th with 1 (6%) in 11th with 2 (6%) in 9th with 3 (0%) in 7th with 5 (0%) in 5th with 7 (7%) in 5th with 8 (5%) in 3rd with 11 (6%) in 3rd with 12 (6%) 21: 1673.160018 in 11th with 2 (6%) in 11th with 3 (6%) in 9th with 4 (0%) in 7th with 6 (0%) in 5th with 8 (7%) in 5th with 9 (5%) in 3rd with 12 (6%) in 3rd with 13 (6%) 22: 1904.715374 in 11th with 3 (6%) in 11th with 4 (6%) in 9th with 5 (0%) in 7th with 7 (0%) in 5th with 9 (7%) in 5th with 10 (5%) in 3rd with 13 (6%) in 3rd with 14 (6%) 23: 2168.316609 in 11th with 4 (6%) in 11th with 5 (6%) in 9th with 6 (0%) in 7th with 8 (0%) in 5th with 10 (7%) in 5th with 11 (5%) in 3rd with 14 (6%) in 3rd with 15 (6%) 24: 2468.398681 in 11th with 5 (6%) in 11th with 6 (6%) in 9th with 7 (0%) in 7th with 9 (0%) in 5th with 11 (7%) in 5th with 12 (5%) in 3rd with 15 (6%) in 3rd with 16 (6%) 25: 2810.010320 in 11th with 6 (6%) in 11th with 7 (6%) in 9th with 8 (0%) in 7th with 10 (0%) in 5th with 12 (7%) in 5th with 13 (5%) in 3rd with 16 (6%) in 3rd with 17 (6%) 26: 3198.898970 in 11th with 7 (6%) in 11th with 8 (6%) in 9th with 9 (0%) in 7th with 11 (0%) in 5th with 13 (7%) in 5th with 14 (5%) in 3rd with 17 (6%) in 3rd with 18 (6%) 27: 3641.607487 in 11th with 8 (6%) in 11th with 9 (6%) in 9th with 10 (0%) in 7th with 12 (0%) in 5th with 14 (7%) in 5th with 15 (5%) in 3rd with 18 (6%) in 3rd with 19 (6%) 28: 4145.584219 in 11th with 9 (6%) in 11th with 10 (6%) in 9th with 11 (0%) in 7th with 13 (0%) in 5th with 15 (7%) in 5th with 16 (5%) in 3rd with 19 (6%) in 3rd with 20 (6%) 29: 4719.308322 in 11th with 10 (6%) in 11th with 11 (6%) in 9th with 12 (0%) in 7th with 14 (0%) in 5th with 16 (7%) in 5th with 17 (5%) in 3rd with 20 (6%) in 3rd with 21 (6%) 30: 5372.432416 in 11th with 11 (6%) in 11th with 12 (6%) in 9th with 13 (0%) in 7th with 15 (0%) in 5th with 17 (7%) in 5th with 18 (5%) in 3rd with 21 (6%) in 3rd with 22 (6%) 31: 6115.944983 in 11th with 12 (6%) in 11th with 13 (6%) in 9th with 14 (0%) in 7th with 16 (0%) in 5th with 18 (7%) in 5th with 19 (5%) in 3rd with 22 (6%) in 3rd with 23 (6%) 32: 6962.355251 in 11th with 13 (6%) in 11th with 14 (6%) in 9th with 15 (0%) in 7th with 17 (0%) in 5th with 19 (7%) in 5th with 20 (5%) in 3rd with 23 (6%) in 3rd with 24 (6%) 33: 7925.903646 in 11th with 14 (6%) in 11th with 15 (6%) in 9th with 16 (0%) in 7th with 18 (0%) in 5th with 20 (7%) in 5th with 21 (5%) in 3rd with 24 (6%) in 3rd with 25 (6%) 34: 9022.801386 in 11th with 15 (6%) in 11th with 16 (6%) in 9th with 17 (0%) in 7th with 19 (0%) in 5th with 21 (7%) in 5th with 22 (5%) in 3rd with 25 (6%) in 3rd with 26 (6%) 35: 10271.503223 in 11th with 16 (6%) in 11th with 17 (6%) in 9th with 18 (0%) in 7th with 20 (0%) in 5th with 22 (7%) in 5th with 23 (5%) in 3rd with 26 (6%) in 3rd with 27 (6%) 36: 11693.017939 in 11th with 17 (6%) in 11th with 18 (6%) in 9th with 19 (0%) in 7th with 21 (0%) in 5th with 23 (7%) in 5th with 24 (5%) in 3rd with 27 (6%) in 3rd with 28 (6%) 37: 13311.261804 in 11th with 18 (6%) in 11th with 19 (6%) in 9th with 20 (0%) in 7th with 22 (0%) in 5th with 24 (7%) in 5th with 25 (5%) in 3rd with 28 (6%) in 3rd with 29 (6%) 38: 15153.460957 in 11th with 19 (6%) in 11th with 20 (6%) in 9th with 21 (0%) in 7th with 23 (0%) in 5th with 25 (7%) in 5th with 26 (5%) in 3rd with 29 (6%) in 3rd with 30 (6%)
P.S. Вот более точная реализация вышеприведённой последовательности на 40 строк (использовалась слегка модифицированная программа, которая начинает считать со 100 Гц и с чуть большей точностью):
40
Code:
TRY 2^0.186800 0: 100.000000 1: 113.823623 2: 129.558170 3: 147.467803 4: 167.853195 5: 191.056587 6: 217.467529 7: 247.529419 8: 281.746951 in 3rd with 0 (6.4%) 9: 320.694586 in 3rd with 0 (6.4%) in 3rd with 1 (6.4%) 10: 365.026195 in 3rd with 1 (6.4%) in 3rd with 2 (6.4%) 11: 415.486039 in 3rd with 2 (6.4%) in 3rd with 3 (6.4%) 12: 472.921260 in 5th with 0 (5.7%) in 3rd with 3 (6.4%) in 3rd with 4 (6.4%) 13: 538.296110 in 5th with 0 (7.1%) in 5th with 1 (5.7%) in 3rd with 4 (6.4%) in 3rd with 5 (6.4%) 14: 612.708132 in 5th with 1 (7.1%) in 5th with 2 (5.7%) in 3rd with 5 (6.4%) in 3rd with 6 (6.4%) 15: 697.406592 in 7th with 0 (0.3%) in 5th with 2 (7.1%) in 5th with 3 (5.7%) in 3rd with 6 (6.4%) in 3rd with 7 (6.4%) 16: 793.813446 in 7th with 1 (0.3%) in 5th with 3 (7.1%) in 5th with 4 (5.7%) in 3rd with 7 (6.4%) in 3rd with 8 (6.4%) 17: 903.547220 in 9th with 0 (0.3%) in 7th with 2 (0.3%) in 5th with 4 (7.1%) in 5th with 5 (5.7%) in 3rd with 8 (6.4%) in 3rd with 9 (6.4%) 18: 1028.450177 in 11th with 0 (6.9%) in 9th with 1 (0.3%) in 7th with 3 (0.3%) in 5th with 5 (7.1%) in 5th with 6 (5.7%) in 3rd with 9 (6.4%) in 3rd with 10 (6.4%) 19: 1170.619248 in 11th with 0 (6.0%) in 11th with 1 (6.9%) in 9th with 2 (0.3%) in 7th with 4 (0.3%) in 5th with 6 (7.1%) in 5th with 7 (5.7%) in 3rd with 10 (6.4%) in 3rd with 11 (6.4%) 20: 1332.441233 in 11th with 1 (6.0%) in 11th with 2 (6.9%) in 9th with 3 (0.3%) in 7th with 5 (0.3%) in 5th with 7 (7.1%) in 5th with 8 (5.7%) in 3rd with 11 (6.4%) in 3rd with 12 (6.4%) 21: 1516.632880 in 11th with 2 (6.0%) in 11th with 3 (6.9%) in 9th with 4 (0.3%) in 7th with 6 (0.3%) in 5th with 8 (7.1%) in 5th with 9 (5.7%) in 3rd with 12 (6.4%) in 3rd with 13 (6.4%) 22: 1726.286484 in 11th with 3 (6.0%) in 11th with 4 (6.9%) in 9th with 5 (0.3%) in 7th with 7 (0.3%) in 5th with 9 (7.1%) in 5th with 10 (5.7%) in 3rd with 13 (6.4%) in 3rd with 14 (6.4%) 23: 1964.921811 in 11th with 4 (6.0%) in 11th with 5 (6.9%) in 9th with 6 (0.3%) in 7th with 8 (0.3%) in 5th with 10 (7.1%) in 5th with 11 (5.7%) in 3rd with 14 (6.4%) in 3rd with 15 (6.4%) 24: 2236.545184 in 11th with 5 (6.0%) in 11th with 6 (6.9%) in 9th with 7 (0.3%) in 7th with 9 (0.3%) in 5th with 11 (7.1%) in 5th with 12 (5.7%) in 3rd with 15 (6.4%) in 3rd with 16 (6.4%) 25: 2545.716748 in 11th with 6 (6.0%) in 11th with 7 (6.9%) in 9th with 8 (0.3%) in 7th with 10 (0.3%) in 5th with 12 (7.1%) in 5th with 13 (5.7%) in 3rd with 16 (6.4%) in 3rd with 17 (6.4%) 26: 2897.627021 in 11th with 7 (6.0%) in 11th with 8 (6.9%) in 9th with 9 (0.3%) in 7th with 11 (0.3%) in 5th with 13 (7.1%) in 5th with 14 (5.7%) in 3rd with 17 (6.4%) in 3rd with 18 (6.4%) 27: 3298.184043 in 11th with 8 (6.0%) in 11th with 9 (6.9%) in 9th with 10 (0.3%) in 7th with 12 (0.3%) in 5th with 14 (7.1%) in 5th with 15 (5.7%) in 3rd with 18 (6.4%) in 3rd with 19 (6.4%) 28: 3754.112554 in 11th with 9 (6.0%) in 11th with 10 (6.9%) in 9th with 11 (0.3%) in 7th with 13 (0.3%) in 5th with 15 (7.1%) in 5th with 16 (5.7%) in 3rd with 19 (6.4%) in 3rd with 20 (6.4%) 29: 4273.066902 in 11th with 10 (6.0%) in 11th with 11 (6.9%) in 9th with 12 (0.3%) in 7th with 14 (0.3%) in 5th with 16 (7.1%) in 5th with 17 (5.7%) in 3rd with 20 (6.4%) in 3rd with 21 (6.4%) 30: 4863.759540 in 11th with 11 (6.0%) in 11th with 12 (6.9%) in 9th with 13 (0.3%) in 7th with 15 (0.3%) in 5th with 17 (7.1%) in 5th with 18 (5.7%) in 3rd with 21 (6.4%) in 3rd with 22 (6.4%) 31: 5536.107299 in 11th with 12 (6.0%) in 11th with 13 (6.9%) in 9th with 14 (0.3%) in 7th with 16 (0.3%) in 5th with 18 (7.1%) in 5th with 19 (5.7%) in 3rd with 22 (6.4%) in 3rd with 23 (6.4%) 32: 6301.397874 in 11th with 13 (6.0%) in 11th with 14 (6.9%) in 9th with 15 (0.3%) in 7th with 17 (0.3%) in 5th with 19 (7.1%) in 5th with 20 (5.7%) in 3rd with 23 (6.4%) in 3rd with 24 (6.4%) 33: 7172.479329 in 11th with 14 (6.0%) in 11th with 15 (6.9%) in 9th with 16 (0.3%) in 7th with 18 (0.3%) in 5th with 20 (7.1%) in 5th with 21 (5.7%) in 3rd with 24 (6.4%) in 3rd with 25 (6.4%) 34: 8163.975796 in 11th with 15 (6.0%) in 11th with 16 (6.9%) in 9th with 17 (0.3%) in 7th with 19 (0.3%) in 5th with 21 (7.1%) in 5th with 22 (5.7%) in 3rd with 25 (6.4%) in 3rd with 26 (6.4%) 35: 9292.532991 in 11th with 16 (6.0%) in 11th with 17 (6.9%) in 9th with 18 (0.3%) in 7th with 20 (0.3%) in 5th with 22 (7.1%) in 5th with 23 (5.7%) in 3rd with 26 (6.4%) in 3rd with 27 (6.4%) 36: 10577.097674 in 11th with 17 (6.0%) in 11th with 18 (6.9%) in 9th with 19 (0.3%) in 7th with 21 (0.3%) in 5th with 23 (7.1%) in 5th with 24 (5.7%) in 3rd with 27 (6.4%) in 3rd with 28 (6.4%) 37: 12039.235728 in 11th with 18 (6.0%) in 11th with 19 (6.9%) in 9th with 20 (0.3%) in 7th with 22 (0.3%) in 5th with 24 (7.1%) in 5th with 25 (5.7%) in 3rd with 28 (6.4%) in 3rd with 29 (6.4%) 38: 13703.494229 in 11th with 19 (6.0%) in 11th with 20 (6.9%) in 9th with 21 (0.3%) in 7th with 23 (0.3%) in 5th with 25 (7.1%) in 5th with 26 (5.7%) in 3rd with 29 (6.4%) in 3rd with 30 (6.4%) 39: 15597.813541 in 11th with 20 (6.0%) in 11th with 21 (6.9%) in 9th with 22 (0.3%) in 7th with 24 (0.3%) in 5th with 26 (7.1%) in 5th with 27 (5.7%) in 3rd with 30 (6.4%) in 3rd with 31 (6.4%)
Синхронизацию кадров можно делать путём посылки тишины и затем всех частот (белый шум?) в течении короткого промежутка времени - по идее так можно делать переменную частоту кадров - сколько таких пар тишина-шум было в течении секунды - такая и частота кадров...
если 7я гармоника с отступом в 5% ок, то можно получить 20 строк:
Code:
TRY 2^0.361000 0: 110.000000 1: 141.274739 2: 181.441381 3: 233.028034 4: 299.281588 5: 384.372074 6: 493.655131 7: 634.009089 8: 814.267897 in 7th with 0 (5%) 9: 1045.777132 in 9th with 0 (5%) in 7th with 1 (5%) 10: 1343.108104 in 11th with 0 (9%) in 9th with 1 (5%) in 7th with 2 (5%) 11: 1724.974971 in 11th with 1 (9%) in 9th with 2 (5%) in 7th with 3 (5%) 12: 2215.412625 in 11th with 2 (9%) in 9th with 3 (5%) in 7th with 4 (5%) 13: 2845.289458 in 11th with 3 (9%) in 9th with 4 (5%) in 7th with 5 (5%) 14: 3654.250232 in 11th with 4 (9%) in 9th with 5 (5%) in 7th with 6 (5%) 15: 4693.211343 in 11th with 5 (9%) in 9th with 6 (5%) in 7th with 7 (5%) 16: 6027.565523 in 11th with 6 (9%) in 9th with 7 (5%) in 7th with 8 (5%) 17: 7741.297691 in 11th with 7 (9%) in 9th with 8 (5%) in 7th with 9 (5%) 18: 9942.271007 in 11th with 8 (9%) in 9th with 9 (5%) in 7th with 10 (5%) 19: 12769.015831 in 11th with 9 (9%) in 9th with 10 (5%) in 7th with 11 (5%)
Вот сгенерил звуковой файл в вышеописанном формате (назовём его Vsound20), смиксив прямоугольные сигналы (чтобы были гармоники) - сначала лесенкой каждая частота по отдельности, а потом все - Audacity нарисовал вот такую спектрограмму (логарифмическая шкала от 100 до 16000 Гц), на которой видно, что гармоники не только в большую сторону отражаются (т.е. вверх), но и в меньшую (т.е. вниз):
Attachments:
Vsound20-stairs.jpg [ 124.51 KiB | Viewed 13314 times ]
Vsound20-stairs-linear.jpg [ 177.29 KiB | Viewed 13314 times ]
Тут полоски одинаковой толщины (и гармоники лучше видно)
P.S. Видимо FFT в линейной шкале работает - тут как бы надо выбирать, либо мы генерим картинку, чтобы она в спектрогляделках хорошо выглядела, либо чтобы аппаратно декодилась хорошо в реальной железяке...
При сужении сигналов (чтобы утолкать несколько кадров в секунду) качество сильно ухудшилось - чтобы что-то увидеть пришлось ставить размер окна FFT 512 (а не 2048 как в прошом примере):
Attachment:
Vsound20-stairs2.jpg [ 75.4 KiB | Viewed 13291 times ]
Зато вроде получилось подобрать более-менее приемлемые временные характеристики - при частоте сэмплирования 44100 Гц я тут задаю ширину кадра в 4000 единиц (т.е. в 1 секунду влезет 11.025 кадров) из которых 500 единиц (11мс) это тишина, далее 500 единиц (другие 11мс) это все линии "гудят" (типа синхросигнал - на 110 Гц туда должно влезть 4.5 периода) и оставшиеся 3000 это собственно кадр - тут 20 ступенек у лесенки из которых в нижних частотах всё сливается, однако в высоких частотах чёткость можно увеличить думаю. Если хочется послушать (и посмотреть) это "видео" - MP3 приаттачен внизу...
Я вот уже давно никак не могу найти - в какой-то советской книжке типа "Справочник радиолюбителя" в конце был описание конструкции видеомагнитофона на бобинах и схемотехника его узлов.
Хотя в материале и писали, что это несерьёзно с протягой без БВГ, но всё было описано подробно...
Мне очень захотелось всё это перечитать, когда я увидел вот это:
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