| Re:2² x 3² x 5² x 7² = 44.100 |  |
>Ich dachte das wird eh im Video erklärt?
Das Video erklärt zwar den Zusammenhang mit dem Videosignal, aber die Faktoren sind trotzdem kein reiner Zufall. Der englische Wikipedia Artikel zu NTSC erklärt es:
[https://en.m.wikipedia.org/wiki/NTSC]
The actual figure of 525 lines was chosen as a consequence of the limitations of the vacuum-tube-based technologies of the day. In early TV systems, a master voltage-controlled oscillator was run at twice the horizontal line frequency, and this frequency was divided down by the number of lines used (in this case 525) to give the field frequency (60 Hz in this case). This frequency was then compared with the 60 Hz power-line frequency and any discrepancy corrected by adjusting the frequency of the master oscillator. For interlaced scanning, an odd number of lines per frame was required in order to make the vertical retrace distance identical for the odd and even fields, which meant the master oscillator frequency had to be divided down by an odd number. At the time, the only practical method of frequency division was the use of a chain of vacuum tube multivibrators, the overall division ratio being the mathematical product of the division ratios of the chain. Since all the factors of an odd number also have to be odd numbers, it follows that all the dividers in the chain also had to divide by odd numbers, and these had to be relatively small due to the problems of thermal drift with vacuum tube devices. The closest practical sequence to 500 that meets these criteria was 3×5×5×7=525. (For the same reason, 625-line PAL-B/G and SECAM uses 5×5×5×5, the old British 405-line system used 3×3×3×3×5, the French 819-line system used 3×3×7×13 etc.)
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