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Can I get a 16-bit value from paired 8-bit A-D's?

Can I get a 16-bit value from paired 8-bit A-D's?

Can I get a 16-bit value from paired 8-bit A-D's?

(OP)
Since many 8-bit A-D converters are available, what would I need, generally, to combine 2 8-bit parts to obtain a 16-bit value from an analog signal?  Would I divide the analog value on the front end, or divide it after conversion, assuming my circuit split the signal in the middle?  General answer will be fine - thanks!

RE: Can I get a 16-bit value from paired 8-bit A-D's?

  The circuit you would need is more complex than you imagine.  Your 'first' A/D coverter finds the value to 1 part in 256, and your second must find the error or difference between the 8 bit conversion and the actual input to 1 part in 256.  Consequently you need two A/D converters, one D/A converter, an op-amp or two and some precision resistors.  A 10 or 12 bit A/D is simpler and cheaper.

RE: Can I get a 16-bit value from paired 8-bit A-D's?

Texas Instruments has some pretty reasonably priced 16-bit A/Ds.  Have you considered them?  What sampling rate do you need?

RE: Can I get a 16-bit value from paired 8-bit A-D's?

ve7brz,

you missed the Sample-and-Hold circuit in your description.

RE: Can I get a 16-bit value from paired 8-bit A-D's?

Sorry electricuwe,

  I forgot to mention that.

RE: Can I get a 16-bit value from paired 8-bit A-D's?

Hi, 16 bit is allmost impossible to get for someone of your level of expertise, 12 bit is a more realistic goal.

RE: Can I get a 16-bit value from paired 8-bit A-D's?

(OP)
Yeah, "level of expertise" is putting it pretty generously.  Someone else asked me this question, and he was interested in model rocket telemetry using some 8-bit components he knew of which had high bandwidth - he though 1 gigahertz might have been the number.  So both of us are out of our league.  Thanks for the responses - sounds like with all the requisite circuitry, (sample and hold, for heck's sake...), there's a bit of a bottleneck outside of the high speed of the A/D's.

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