[sdiy] re: interesting digital circuits

[Richard Wentk]

At 18:19 15/12/2004 -0500, tuj wrote:

>The interpolation idea is pretty cool, but I think it would get pretty 
>complex to do more than just a single interpretation between 
>samples.  Unless someone has a clever design for this?  I'm not sure how 
>to do multiple steps between samples without bringing division into 
>play.  If I do that, I'll have to implement more complex timing so I can 
>accomplish all the ops between read/writes, plus buffers, plus multiple 
>ALU's.  Although I suppose right-shifts followed by an add would give a 
>reasonable approximation.  As you can see by my selection of an 8bit ADC, 
>this isn't intended to be hi-fi.

Interpolation on an 8-bit system is a complete waste of time, except as a 
learning exercise. ;-)

If you want to go beyond basic 8 bits you can get much better fidelity by 
companding the audio, or storing a separate extra few bits of 
envelope/level information in parallel with your 8-bits of audio. The 
traditional NE570/571 analogue compander was often used in commercial 8-bit 
delays to stop the sound going completely fghfdghfjgdfgjkkggzssssss.

I still think EQ in the feedback section is the best next step though. :-)

Richard