Signal chirp generator with AD9956

[nikko]

Help please !!,

I need any information for generate signal sine or signal chirp, using a chip AD9956.

I would be very grateful for any help

[titi]

Hi,

I don't known if you have the datasheet for AD9956, so you can find it at : http://www.farnell.com/datasheets/92410.pdf
Here is the link for the Design Tools ADIsimDDS : http://designtools.analog.com/dtDDSWeb/dtDDSMain.aspx
This on-line simulation tool is also usable for other DDS like AD9833, AD9835, AD9851, ...
Here is the schematics Evaluation Board : http://www.analog.com/static/imported-files/eval_boards/559305458856928475134216352159429654403731531568125410736909283644450AD9956_RevE_schem.pdf
Here to find Analog Device softwares for AD9956 for Eval Board and others informations : http://www.analog.com/en/rfif-components/direct-digital-synthesis-dds/ad9956/products/evaluation-boards-kits/index.html

Best regards.

[2N5109]

Hello,

Before the DDS chip is selected for generating a chirp, it is good to remember that synthesizing a chirp with a DDS is actually done by approximating the ramped frequency vs. time with a staircase.  Some fundamental system design is probably in order:  If the step size is sufficiently small (less than your system resolution bandwidth) the steps will not be noticeable.  Due to the large number of bits in typical DDS accumulators it is usually the DDS clock speed which sets the maximum chirp rate.  For example if the desired sweep (chirp) rate is Ksr and the DDS resolution is Fbin, then
Ksr=Fbin/DeltaT
and the time between steps has to be Fbin/Ksr.  This is also the inverse of the DDS clock.  The DDs clock speed is then Ksr/Fbin so you can see for high resolution you need a fast clock.  The AD9956 is like a Swiss Army Knife--it has all kinds of goodies--but you should check that it fundamentally does what you want to do before spending a lot of time programming it. 

I hope this helps,
  2N5109

[nikko]

Hi Titi

Thanks very much.

I am working with AD932.
I need CCS rutines for connect a PIC with AD5932 using 3-wire.


Best regards.

[titi]

Hi nikko,

Here an application document from Analog Device : AN-1044: Programming the AD5932 for Frequency Sweep and Single Frequency Outputs
http://www.analog.com/static/imported-files/application_notes/AN-1044.pdf

Here is an Dutch project with AD5930 that is very close to AD5932 : http://www.mikrocontroller.net/articles/DDS_basierter_Funktionsgenerator_mit_AD5930
Project Documents : http://mexlewiki.hs-heilbronn.de/UserFiles/File/Funktionsgenerator%20DDS/Documentation%20DDS.pdf

On this page http://www.mikrocontroller.net/topic/168134 there are :
  ad5932.h    : http://www.mikrocontroller.net/attachment/71731/ad5932.h
  main.c        : http://www.mikrocontroller.net/attachment/71732/main.c
  drawing pdf : http://www.mikrocontroller.net/attachment/71733/DDS-Funktionsgenerator.pdf



Best regards.

[nikko]

Hi Titi,

I am grateful for your time. The information you share is helpful.

Thanks a lot.