16bit waveform output from dds compiler

[Pier]

Hi,

I'm trying to achieve a 16bit waveform output from dds compiler,  could somebody help me to set it up correctly?

I actually need two different dds and two different ranges with streaming options

1) 27.5hz-7040hz

2) 0.25hz-64hz.

 

First is for an audible range oscillator, second for a control oscillator.

i've been experimenting with the tool and i got  i need to put a higher frequency resolution and so have a phase input up to 64 bits (?) is this right?

 

 

[Ana-Maria Balas]

Hello @Pier,

Did you checked the DDS Compiler IP Guide? I see at pages 13-17  that if you use the Standard Mode of Operation then:

[Pier]

hola, gracias,

i saw already dds compiler guide...but  i don't know really.... that's why i'm asking you because

as following  page 16 formulas (i cannot know what phase increment to use .)

if i say

clk =100 Mhz

B=16

Fout =27.5 Hz

then the phase increment comes out to be 0.018.

so the only way to do it is reduce clock speed to 100khz . is it right?

But also, in this case frequency resolution would be a mere 1.52 hz which is not really good actually ,

and to make it better i would have to higher the bits number of at least 1 bit..

so i still cannot see a way out

 

 

[JColvin]

Hi @Pier,

That is correct. I don't know what phase increment you are wanting, but if you want a phase increment of 18 for example, you can also increase the Fout frequency to 27.5 kHz.

Thanks,
JColvin

[Pier]

Thanks a lot Colvin,

thing is that i would have to control dds thru an external 15bits input. i made lots of calculations but cannot see a precise outcome as i cannot fit the input range to the targeted frequencies mentioned without approximation. Do you have any hints to make this 0-32767 value to match the 27.5hz-7040hz range?.

hope anybody can help , otherwise the only chance would be a big lookup table...

best regards