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AD5930 wrong output waveform

Question asked by bazsogabor on Dec 7, 2013
Latest reply on Dec 13, 2013 by bazsogabor

Hi!

I built AD5930 DDS with pic.

Q=52MHz or 34MHz

 

Output=or other...

 

My code:

write_vivo(0b0000011011111011); // 16 bit config bits

write_vivo(0b1100000000000000+0x93f); // (o mod 4096)); // fstart lower  lsb 12bit 13,56MHz=1001

write_vivo(0b1101000000000000+0x425); // (o div 4096)); // fstart higher msb 12bit 13,56=1599

write_vivo(0b0001111100011111); // num of increment ez nem kell

write_vivo(0b0010000000000000+1); // + (o mod 4096)); // LSB 12bit

write_vivo(0b0011000000000000+100); // + (o div 4096)); // positive high deltaf 11bit

 

write_vivo_step(); // az elso leptetes utan indul el a kimeneten a sinus

 

finaly: the output  freqvency is good, but not SINUS!

Please see attach..

 

What is the prblem?

I modify power supply.

Original:vdd= +5v va=5v,

now vdd=5v, va=3.3V with ferrire vaweform is bad..

 

Thanx

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