AD9834 output AC coupling

Discussion in 'The Projects Forum' started by DreamCatch16, May 11, 2014.

  1. DreamCatch16

    Thread Starter New Member

    Feb 10, 2014

    I have a very basic question about AC coupling the output of the AD9834,
    Please what is the best practice? do I put the passive high pass filter just after the output of the DDS or I have to amplify first than apply a passive high pass filter?

    The second is? do I have to use small or high cap for the high pass filter? "and adjusting the resistance accordingly"

    Thank you in advance for your help.
  2. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    The AD9834 should have a LOW pass filter to remove the digital steps, then it's sine output will be analogue.

    Then just put it through a capacitor to AC couple it.

    The datasheet for the IC should have examples of output components like the low pass filter and AC coupling. You should not need an output amp unless you need a higher AC voltage out, or need to drive a low impedance (ie a large load).