Ricewind
Newbie level 6
Hello,
i am currently using a AD9959 DDS in order to generate various control senoids for a analogic circuit. The problem I find is that the output amplitude varies depending on the frequency I set. For example, I get 2.85 Vpp at 55 MHz and 554 mVpp at 20 MHz.
I know I can make the output amplitude lower through OSF control and thus having the output at similar voltages... the problem at this is that the voltage will be the smallest one of the ones I can get and it is not enough to operate the following circuit without an intermediate amplifying stage.
I do not understand why these different amplitudes come out, as the DAC should be able to generate signals with the maximum amplitude for all the frequency range, so the problem will be likely to be internal to the digital stage of the DDS.
Any help at this?
Thank you in advance.
i am currently using a AD9959 DDS in order to generate various control senoids for a analogic circuit. The problem I find is that the output amplitude varies depending on the frequency I set. For example, I get 2.85 Vpp at 55 MHz and 554 mVpp at 20 MHz.
I know I can make the output amplitude lower through OSF control and thus having the output at similar voltages... the problem at this is that the voltage will be the smallest one of the ones I can get and it is not enough to operate the following circuit without an intermediate amplifying stage.
I do not understand why these different amplitudes come out, as the DAC should be able to generate signals with the maximum amplitude for all the frequency range, so the problem will be likely to be internal to the digital stage of the DDS.
Any help at this?
Thank you in advance.