Homemade DDS PIC Micro Function Generator

This function generator is fully developed by myself from schematic diagram to pcb layout. The PCB is also made by myself using the UV method. The AD9834 Direct Digital Synthesis (DDS) from Analog Devices makes it easy to design a low-cost, but yet high-performance function generator. One of the benefits of using DDS for function generator is that the output signal has very low distortion and frequency can be controlled digitally. The DDS and the display are driven by PIC16F876A PIC microcontroller which software is written with mikroC.This function generator can produce output frequency from 1Hz to 10MHz which is adequate for most of the applications.The output amplitude can be controlled digitally with 1024 steps thanks to the MAX5481 digital potentiometer from Maxim.

Schematic download link:
http://rapidshare.com/files/389093146/schematic.png

Category:

Science & Technology

Tags:

• Homemade
• DDS
• PIC
• Microcontroller
• Function
• Signal
• Generator
• Sine
• Triangle
• wave
• output

[navarromoral]

Hello! First of all this is a great project! I have studied the schematic but I did not understand why you used the IC MAX5481, as it has a BW of some Khz, how can you reach 10MHz?. What I am missing??

Thanks!!

[iceman2312]

@navarromoral I have checked the data sheet of MAX5481 and the bandwidth is as you said only 250khz @ code 01111. When I shot this video the wiper was at 100%, may be that was the reason why I could get the output at 10MHz without significant attenuation

[Programmingrocks]

Awesome, But how did you compensate for the Sinc Rolloff ??. I didn't find anything in your schematic.

[iceman2312]

@Programmingrocks Yeah, you are right. I don't have any compensation for that. Hope someone could suggest with simple but clever enough so that it can fit within the current pcb

[iceman2312]

@iceman2312 There is a solution on analog website regarding how to compensate the issue. Search for application note AN-837

[iceman2312]

@Programmingrocks There is a solution on analog website regarding how to compensate the issue. Search for application note AN-837

[Yitzchakification]

Great job , I would like contact you I have a project maybe you can do this , bretzlev@gmail.com

[sniper757575]

Hi iceman2312, can you send me e source code of this project?

Thank you

[charlesgatofree]

this is funny this project is use in the future

[nwhiggins]

Why did you use averaging in the scope... that doesn't show the real output of the function generator

[the1cyrus]

song name?