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AD9833 register calculations (frequency)

Question asked by AlanGC on Apr 25, 2016
Latest reply on Apr 28, 2016 by mcee

Hi All

I'm trying to interface AD9833 to 18F452 , the hardware works fine. If I use your calculator link and send the hex code

you suggest then all works fine and accurate. I'm using a 25 Mhz clock to the device.

 

AD9833 Device Configuration Assistant | Design Center | Analog Devices

 

My problem is that I'm making an error in the calculation or there is a bug in my complier. I followed your application note AN1070 and my calculation was the same, but higher frequency give a massive error. 

 

Could you show me how your calculator arrives at  2100 5C29 4A3D 9C29 8A3D C000 E000 2000 for a 4MHZ output @ 25Mhz. Im only interested 5C29 4A3D 9C29 8A3D for Frequency register 0 say.

 

AN1070 gives a simple example , could you repeat this for 4MHZ ?

 

Thanks in Advance.

 

Alan

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