Filter-wise...Does anyone know how to convert a slope of dB/decade to dB/octave?
Another thing that just occured to me, I always just took for granted than 3dB represented doubling the power and that 6dB was doubling the amplitude. But it seems this is incorrect. Just like power, a 3dB increase in amplitude still respresents a doubling of the amplitude. However, a 3dB increase (x2) in amplitude results in a 6dB increase (x4) in power.
If you are interested in power, that's great and all. But as far as many filters go, aren't we often more interested in the amplitude rather than the power? For example, you might say "if the frequency doubles I want the amplitude to drop by half". You don't say "I want the power in the signal to drop by half." So why does it seem that we seem to speak power-wise for such situations? For example, the cutoff frequency is defined as the -3dB point for POWER...not amplitude. Why was it defined in terms of power rather than amplitude (rather than 0.707% of the original amplitide, or half the original amplitude?) Wouldn't have that been more useful/practical?
I'm starting to see why the one forum member finds decibels to be too vague (was it Duffy?)...or rather people are too vague when using it. I've edited this post about 12 times so far because I thought I found an answer to something and put it in the post which raised another question, but it turns out to be wrong so I removed it.
Another thing that just occured to me, I always just took for granted than 3dB represented doubling the power and that 6dB was doubling the amplitude. But it seems this is incorrect. Just like power, a 3dB increase in amplitude still respresents a doubling of the amplitude. However, a 3dB increase (x2) in amplitude results in a 6dB increase (x4) in power.
If you are interested in power, that's great and all. But as far as many filters go, aren't we often more interested in the amplitude rather than the power? For example, you might say "if the frequency doubles I want the amplitude to drop by half". You don't say "I want the power in the signal to drop by half." So why does it seem that we seem to speak power-wise for such situations? For example, the cutoff frequency is defined as the -3dB point for POWER...not amplitude. Why was it defined in terms of power rather than amplitude (rather than 0.707% of the original amplitide, or half the original amplitude?) Wouldn't have that been more useful/practical?
I'm starting to see why the one forum member finds decibels to be too vague (was it Duffy?)...or rather people are too vague when using it. I've edited this post about 12 times so far because I thought I found an answer to something and put it in the post which raised another question, but it turns out to be wrong so I removed it.
Last edited: