How to adjust the output signal from an AD9833 frequency module?

Other Hardware General Electronics
1

I am in the planning stages for a simple frequency generator based on the commonly available AD9833 frequency module (example on eBay).

The output from the module is a signal between 0V and about 600mV.

Can someone suggest or point me to a reference that will have circuit design or information to:

  1. Shift (bias?) the output so that it swings +/-300mV around 0V. Variable shifting would be even better, using something like a pot.

  2. What is a good model of opamp to use for amplifying the signal, assuming the availability of a +/-12V split supply.

  3. Is there anything else I should be doing, or is best practice, to condition the output before it is used?

2

Its a current sourcing DAC (with optional load resistor) from a look at the datasheet - probably
just want a current->voltage converter opamp circuit(*), then the bias is set from the non-inverting
input. (But check the output voltage compliance range of course, as with any current source)

(*) Second one on this page: Custom Sensor Solutions, Inc. - Op Amps (continued)

3

Thanks MarkT.

4

If you want clean sine waves you might want to add a low pass filter cutting off anything above about 10 MHz.

Russell.

5

Thanks russellz. Still in planning waiting for my part to arrive.