Audio Cassette formats; what about ADAM? - test-drb@ccmp.vtda.org

30 Nov 1998

...
   I can't
imagine why 8 bits wouldn't be sufficient, given the 
 frequency range of a cheap cassette player.  I recently acquired Considering that
most (all?) home computers feed the cassette input into 
a schmitt trigger (essentially 1-bit sampling), and that the level of the 
input signal is set by twidding the recorder's volume control until it 
loads, so it's not that critical, I would think 8-bit sampling was easily 
good enough. 
8-bits ought to work just fine.  One fine point, which won't hit you
until you try to do some decoding: some tape formats are polarity
sensitive (they use a variant of Manchester encoding).  If at all
possible, you should try to figure out whether your tape player/digitizer/
recorder/player chain inverts are not.

Tarbell-format tapes are (speaking from experience!) polarity-sensitive.
Apple ][ tapes aren't.  Kansas-City format tapes aren't.

Tim. (shoppa(a)trailing-edge.com)