[sdiy] reducing amount of bits

[Michael Boracci]

This seems like really simple thing to do, but I'm not gettin it yet. Is it
as easy as NOT allowing the output DAC to see all the available bits and
just using the top few bits to represent a full scale signal to the DAC?

 For example: If we had a 16 bit word and only used the top four bits ( MSB
down ) to feed the DAC would that be it?


Michael

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Grant Richter
Sent: Friday, September 05, 2003 8:26 PM
To: MED; synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] reducing amount of bits


> Okay, if i have a 5V p-p signal centered at 2.5v and I feed it into the
ADC
> (set to have 5v max), using all of its bits will work. But if I cut out,
say,
> the bottom half, will I be left with a 2.5V max positive half-wave, then a
> flatline for half a cycle, and then another positive halfwave? Or do ADCs
> translate the information so that dropping out bits leads to less and less
> *detail* but still full amplitude?
> Or is it that some ADCs do it one way and others do it another?
> I don't know any of the keywords for adc/dac selection but I could've
sworn
> someone had just done this grungifier project recently...

Just drop out the bits from LSB (least significant) to MSB. You will keep
the same amplitude, but lose detail.

Bank 6 of the "Socket Rocket" EPROM for the Blacet Mini-Wave does this from
8 bits down to 1 bit.




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