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Comments · 6
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Re:Go get a Realtek ethernet card
Eh, a 10/100 card is overkill for an LC II... just get an old ISA NE2000 clone from Goodwill or something. Wedge the card into one of those slots off to the right; it'll work fine. NE2000 drivers are really easy to find too.
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Re:Change the font size!
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Re:Change the font size!
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Re:*ahem*
And just to show you that it even works with a 918Hz sine wave, I've made another picture. Reconstructing the samples gives you a stepped sine wave... yes, it has harmonics in it, but none of them are under 22050Hz. Filtering 'em out once again gives you a nice clean sine wave.
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A visual aidCan't you _see_ this?? Doesn't your math acknowledge this? These are not only measurable distortions but the problem is still present even _completely_ in the theoretical realm.
Sure, I can see it... my math acknowledges it, takes it into account, and works perfectly. Sometimes math isn't intuitively obvious, even though it all works out in the end.
Here, look at some pictures I made... they're kinda quick and dirty, but they should get the point across:
For the 14700Hz picture, I plotted a 14700Hz sine wave, then marked the sample points in red. Then, in the next picture down, I plot the square wave signal made by the samples. As you say, it's not symmetrical, even though the original sine wave was. Now, I write the samples out to a file, and load it into Goldwave, a sound editing tool (I picked Goldwave because I'm vaguely familiar with it, and know that it does filtering). The third picture is how the sample looks in Goldwave. For visual purposes, and because Goldwave only works on digitally sampled files, the file loaded into Goldwave actually has each sample repeated 16 times, so it'd actually be a 918.75Hz tone if played back at a 44100Hz sampling rate. This doesn't invalidate my point though; remember that in the real world, pictures 2, 3, and 4 are analog signals, without any sampling rate. Now, I tell Goldwave to do a low pass filter, with a cutoff frequency of 919Hz. Voilà, I get a nice symmetrical sine wave back.The 14600Hz picture is the same, and yes, the square wave does look like it's been modulated. But do a lowpass filter on it, and it's all fixed
Ain't math grand?
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A visual aidCan't you _see_ this?? Doesn't your math acknowledge this? These are not only measurable distortions but the problem is still present even _completely_ in the theoretical realm.
Sure, I can see it... my math acknowledges it, takes it into account, and works perfectly. Sometimes math isn't intuitively obvious, even though it all works out in the end.
Here, look at some pictures I made... they're kinda quick and dirty, but they should get the point across:
For the 14700Hz picture, I plotted a 14700Hz sine wave, then marked the sample points in red. Then, in the next picture down, I plot the square wave signal made by the samples. As you say, it's not symmetrical, even though the original sine wave was. Now, I write the samples out to a file, and load it into Goldwave, a sound editing tool (I picked Goldwave because I'm vaguely familiar with it, and know that it does filtering). The third picture is how the sample looks in Goldwave. For visual purposes, and because Goldwave only works on digitally sampled files, the file loaded into Goldwave actually has each sample repeated 16 times, so it'd actually be a 918.75Hz tone if played back at a 44100Hz sampling rate. This doesn't invalidate my point though; remember that in the real world, pictures 2, 3, and 4 are analog signals, without any sampling rate. Now, I tell Goldwave to do a low pass filter, with a cutoff frequency of 919Hz. Voilà, I get a nice symmetrical sine wave back.The 14600Hz picture is the same, and yes, the square wave does look like it's been modulated. But do a lowpass filter on it, and it's all fixed
Ain't math grand?
