Query regarding AD9850 chip for a DIY function generator using

Discussion in 'General Electronics Chat' started by portreathbeach, May 9, 2015.

  1. portreathbeach

    Thread Starter Active Member

    Mar 7, 2010
    143
    5
    I have ordered an AD9850 function generator module, like this one.....

    http://mmreference.com/product/ad9850-dds-signal-generator/

    If you look at the schematic, it shows that the VINN (negative voltage for comparitor) is connected on a pot that goes from VCC to ground and they have left the VINP (positive voltage for comparitor) open.

    Am I right in thinking that with this setup, I will only get positive sine waves out of the device?

    If I were to remove the pot and the cap and connect +5v and -5v to these pins, would I get a proper sine wave out of it which went above and below 0v?


    I was thinking if this was the case, I could use something like a NMH1205S.....

    http://uk.farnell.com/murata-power-solutions/nma1205sc/converter-dc-dc-sil-1w--5v/dp/1021435

    as I have a few hanging around.


    Also, it says that in the configuration that the board is currently in, that the pot will alter the output amplitude for sine waves (which I understand), but it says it also alters the square waves duty, as if to be able to use it for PWM. How does this work by simply altering the VINN pit with the pot?
     
    Last edited: May 9, 2015
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