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DDS AD9959 Phase Offset between 4-channels

Question asked by Doyoul on Aug 10, 2018
Latest reply on Aug 10, 2018 by mcee

Hello

 

I have two DDS AD9959.

I did experiment for synchronization of each DDS 4-channels using 'manual I/O update' button in supplied software.

The result is follow.

1. DDS1                                                                                      2. DDS2

                 Figure 1. DDS1 synchronization                                       Figure 2. DDS2 synchronization

 

In the figure 1, the channel 2 signal has amplitude offset and phase offset. 

The phase offset is about 7 degree.

I experimented again, however the amplitude/phase offset is almost constant.

 

I could't find the range of amplitude/phase offset in the datasheet when the 4-channel output is synchronized.

I wonder if the amplitude/phase offset above figure is reasonable.

 

And, I want perfect synchronization of 4-channels that meas the amplitude and phase of all channels are same.

Could you tell me how to synchronize without phase offset?

I'm thinking about whether I should use a phase detector.

 

Thank you for reading.

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