AnsweredAssumed Answered

AD9911 modulation

Question asked by Tola on Nov 24, 2010
Latest reply on Dec 10, 2010 by DSB

Hello all,

I’m trying to realize amplitude modulation on the DDS AD9911. But I do something wrong. For example, I want to implement 2-Level Modulation without RU/RD. I write to the DDS:

CSR - 0x22

FR1  - 0x00,0x00,0x00

CFR - 0x40,0x03,0x03

CTW0 - 0x49,0xBA,0x5E,0x35   // 36 MHz if sysclk=125MHz

ACR - 0x00,0x13,0xFF

CTW1 - 0xFF,0xC0,0x00,0x00

I don’t see any amplitude on a spectrum analyzer, when P1=’0’ or P1=’1’.

 

When I write to the DDS:

CSR - 0x22

FR1  - 0x00,0x00,0x00

CFR - 0x00,0x03,0x02

CTW0 - 0x49,0xBA,0x5E,0x35   // 36 MHz if sysclk=125MHz

ACR - 0x00,0x13,0xFF

I see the amplitude with frequency of 36 MHz.

How I can implement a modulation?

 

regards,

 

Tola.

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