Peter, you have some misinformation yourself, here.
* Peter Jaques <[EMAIL PROTECTED]> on Tue, 05 Jun 2001
| for uncompressed 16 bit stereo pcm, you're essentially dealing with a
| square wave of 16 bits/channel * 2 channels * 44100 Hz = 1411200 Hz.
| that's extremely high to just spit onto what is mechanically no different
| from a metal cassette.
The highest frequency that 16-bit PCM can achieve is 22.01kHz, and is
represented by 16 "on" bits plus the frame. Those 16 "on" bits take up
exactly the same ammount of space as one frame of dead silence, 16 "off"
bits. Frequency has no direct relevance to how much space is required to
store the signal, only resolution of the sampling.
| we know that analog has no problem (other than the well-known problems of
| cassettes;) putting this much information on a cassette (since the
| highest frequency involved is around 21000 Hz even on really high end
| gear), so the original poster was correct in that digital audio requires
| a lot more "space" on the tape. this is why dat/dss use rotating heads &
| dcc uses compression.
DAT uses helical scan because it is cheap and efficient. It is cheaper to
make a small drum move quickly than it is to make the whole mechanism move
quickly. Helical scan uses more of the media surface than linear
mechanisms, which makes them more efficient. That is why VHS and 8mm video
uses helical scan, too.
DCC uses bitwise reduction because in order to maintain compatability with
analog cassettes it uses the same heads, which are more than 500% larger
than they need to be for data storage given the media. Because the heads
are relatively huge (see my previous note about head size) the data density
is very low. If DCC had read/write heads 1/5 the size they are, then
bitwise reduction would be unnecessary.
No, the original poster is not correct in that digital audio requires more
"space" on the tape than analog.
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