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time-dependent phase shift with DDS

Question asked by LLDKong on Jan 16, 2016
Latest reply on Jan 18, 2016 by LouijieC

Hi there,

  I received a AD9910 and AD9959 last week. I am planning to create a sine wave of the form sin(2*pi*f*t + 2*pi*g(t)*t)

 

where f is an constant frequency of 60MHz, g(t) is a time dependent function, one form I am trying is of linear function like g(t)=4.5*t

 

It is easy to gain the output if g(t) is zero or any constant but if it is a function like 4.5*t, is AD9910/AD9959 appropriate for that purpose? How to do that.

 


I try the eval board some times ago to produce a sine wave of 60MHz without phase shifted. I can see a very good waveform. Also, I try the RAM mode to produce a different waveform. But I am thinking to produce a pulse train (12 pulses total), each pulse is of sin(2*pi*f*t) and apart like 2.5ms, do I have to create the waveform data and put them in the RAM to produce that train? But since the frequency is 60MHz, it seems the number of samples is quite a lot and I think it doesn't fit those samples in the RAM. Any other way to create those train? How do I control it will stop after output 12 pulses?

 

Thanks.

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