ADAU1701 DAC DC voltage
Hi, I suppose to know that DC source block, in SigmaStudio, with value 1, should generate a full-scale output. So I expect to read at DAC output a full-scale DC voltage corrisponding to 3V (as it's write on datasheet). But this doesn't happen, i wonder why.
I'd need to obtain a DC value output from DAC to drive a VCA gain control pin.
Maybe I'd need to use some other block instead of a DC source, but which one? Could anybody give me some hints, please?
Thanks to all,
regards
leonxp.
Audio Signal Processors
SigmaDSP Audio Processors
adau1701
Hi,
The DC source is the correct way to put a constant into your signal flows, and 1.0 is full scale. However, the DACs are AC-coupled, thus cannot respond to such an input. See this post for more info:
https://ez.analog.com/message/37624#37624
Bob
Hi leonxp,
Actually now that I tried it, it appears that (at least for the ADAU170x), the DACs are DC-coupled internally. For example, the circuit below produces a variable voltage from approx. 0.2 -- 2.8 volts DC at the DAC outputs, as measured before the usual DC blocking cap:
Best regards,
Bob
Nice, I introduced a circuit board that rectify an AC signal like a sine outgoing from a DAC.
Now I must try this solution. Thanks.
Regards,
Leo
As it turns out, this works well for sending level info directly to a uC's analog input. The interpolator's slope is nonlinear to expand the low levels, and negative since the ADAU1701's DACs invert.
Hi Bob,
If I need to use this board, then do I have to remove this reconstruction filter to generate DC output?
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