Electronics > Beginners

DIY Function Generator

<< < (11/14) > >>

Kleinstein:
External RAM to sample data can be rather fast, but this would need something like an FPGA / CPLD to generate the address sequences. To have a good arb.- generator one might also needs a more or less fine adjustable clock one when to update the clock / data - this is different from an DDS where the clock is fixed.
 

Brutte:
Here I attach the "AWG STM32L.c", that includes all the core functionality of an arbitrary waveform generator for STM32L152RB. You need to link that with peripheral library (available from STM).

It outputs a content of "sin_lut.c" via DAC2 on PA5, trigger output is on PB10 and MCO is on PA8.

I have removed all the USB related stuff as my USB is a mess.



eeFearless:
Here is a DDS design from the AARL archives, complete with reconstruction filter and output leveling:

http://www.arrl.org/files/file/QEX_Next_Issue/May-Jun_2013/Fernandes_QEX_5_13.pdf

Vtile:
I could have swear that someone replied to the OPA aproach. What I quickly looked up ie. Tektronix CFG280 function generator 0..11MHz (20Vpp) is build around handfull of uA741s. With much more functionality than one needs to get started. Also there is discrete Wien-Bridge sine oscillator designs (from tubes to transistors) with Pot-selectable output from few tens to few kiloherts outputs, such can also be modified to have other wave froms as output with a few extra components (mainly OPAs and comparators).

(These are also programmable, but the programming language is hardwiring.)

rstofer:

--- Quote from: eeFearless on January 17, 2017, 04:03:03 pm ---Here is a DDS design from the AARL archives, complete with reconstruction filter and output leveling:

http://www.arrl.org/files/file/QEX_Next_Issue/May-Jun_2013/Fernandes_QEX_5_13.pdf

--- End quote ---

That's a great document!  It clearly shows that the DDS chip (AD9833) is the least of the problem.  The author wraps a barn full of stuff around the outside.
Really nice work!

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod