ZX Power #03
31 декабря 1997 |
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Miscellaneous - Trouble with AY (wrong clock frequency).
5m Trouble AY (C) 1997 Tan________________________________ Usem big hello! A vyznaete that with me proizoshlaodna a very interesting story? No? Well then, listen! Recently, a few days ago, popadaetsyamne magazine "FLASH TIME 1", and I, of course, wanted to, so ska show to read. I read it, Chi-melting, and suddenly I see: juicy interesting article entitled "Trouble AY". Well, of course, yaotkryvayu an article and start eechitat. And just across the bore-How many moments I begin oschu-schat weight around my ushey.Ya think: "Shaw is suddenly happened?" I went to the mirror and see: tons of noodles, like the vines, hanging from my ears. I think: "But!" A state of shock ... And now the jokes aside and Listen, kids, the most truth. To begin with a few words to those who do not know. Tov.Amadeus Voxon of Flash inc. wrote article in his magazine Flash Time. Contents of the article say something like: "All muses. Editors at Speccy lie, ie, notes that are played in them, the frequency is not coincide with the international table of frequency notes. And we need to remake the editors to be compliance. " Immediately I will say: - Yes, indeed, this problem has been brewing long time ago and it was necessary to solve at the dawn of "AY-connection." But whether there was nobody to this engage in, or something else, but actually match the music was. Here's why: the thing is that corporate Speccy AY clocked on the frequency, the withdrawn with the ULA. Because ULA to go out to work in the PAL, then the signal color subcarrier, which is equal 4.43361875 MHz, took up his base and then divides by 2.5 decreased to 1.7734475 MHz, was applied to the clock input AY. A on our machines are usually taken as a basis 14 MHz (clock computer) and further internal divider companies divide at 8 and get 1.75 MHz. Frequency of playing the notes is calculated by the formula: Fnoty = (Fclk/16) / T, where Fclk - clock frequency AY, T - period music. Figure 16 in the formula shows that in AY is an additional frequency divider 16. The fallacy of the formula, which suggested Voxon, that instead of 16 he stood 12. It turns out that when one the same period, the frequency of sounding notes in the company, shovels competence diverges 1.0133986 times. And so all zabugornye muses. editors in our company losing note with a different frequency, different from the standard. A as creators of our music. editors take the constant periods Music from zabugornye editors, then discrepancy remained in theirs editors. A few words about international standard frequency notes. Well, firstly, I will tell you a little history. Long ago, when ancient people were running for mammoths and other wildlife, using the stone axes and bows and arrows, hunting in his spare time, they rested at a fire. Someone in the head The thought occurred to indulge bowstring bow - History does not remember but the fact remains, and a silly old man began to pull the string. At the same string gave out some sounds, amuse a tired man. Under human hand was another onions, and some fun it over him. This Onion published a different sound, but He was very much like the first ... In short - and then, a lot later, there were musical tools. Musicians notice feature, consisting in that a collection of some three sounds together is seen especially nice. As it turned out, it turned out to be sounds with frequency ratio 4:5:6. Continued in the next issue ... ________________________________
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