DAC bit res.

[JOHN VOLANSKI]

The easy way to figure out the number of discrete levels for a DAC would   
be to take 2 to the power of the number of bits in the DAC.  So for an   
8-bit DAC, 2 to the 8th power is 256.  So there are 256 discrete levels   
(0 to 255) that can program the DAC to linearly drive over it's full   
analog output swing.  To find out what the lowest amount of resolution is   
for the DAC, divide the full scale output voltage swing by 2 to the N   
minus 1.  So for an 8-bit DAC that swings 0 to 10 volts, 10/255 = .0392,   
which means that the LSB is equal to 39.2mV.  You then need to determine   
if being able to control your voltage with a resolution no smaller than   
39.2mV is going to give you the kind of accuracy you need to control your   
VCO.
JV

 ----------
From:  Duane R Balvage[SMTP:dbalvage at ptdcs2.intel.com]
Sent:  Thursday, February 27, 1997 12:35 PM
To:  synth-diy
Subject:  DAC bit res.





    - Another dumb question, guys!


        How many bits of resolution for frequency control would you use?

    8? 10? 12? More? I am *trying* to figure out the necessary accuracy   
for

    a polyphonic synth with ANALOG oscillators! My guess is you don't   
want

    the tuning to drift more than a few cents in either direction. Any

    help in this matter will be GREATLY appreciated!


                                      - Duane

                                     _--____---_-_synth nut
 --
           

  "Two nothings is nothing, thats mathematics, son...." - Foghorn Leghorn   
   

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