Function Generator (DIY)

[Mosaic]

Hi all:
I want to make a DIY function/sig. generator, perhaps based on the ad5932
https://www.electro-tech-online.com/custompdfs/2013/04/AD5932.pdf.

I am upgrading my home workshop and I don't think I need all the $$$ bells and whistles in commercial units.

There seems to be a lack of DIY projects for this.

Any advice on pursuing this?

 

[ronsimpson]

There is a 'demo board' for the AD5932. The PCB layout is very important.

There are DDS projects. Search for "AD9850 DDS Signal Generator Module 0-40MHz 2 Sine Wave And 2 Square Wave Output". Many parts like this!

https://www.amazon.com/SG1005-Signal-Generator-Source-Function/dp/B008N7M5KU/ref=pd_sim_sbs_lg_3

 

[Mosaic]

Ok...how about a compromise... a KIT?

This one looks promising
https://www.ebay.com/itm/261114462307#shId

Eval:
https://www.youtube.com/watch?v=Ghypzo6YK6c

Has a couple minor probs, but it should be good enuf for a home shop.Since it's a thru hole kit I can prob add more pwr line decoupling (10nf for 25Mhz?) with a 10uF (SMD) local backup to lower it's impedance & and place an esr transorb on the inner side of the 49 ohm output resistor for ESD.

Also I might want to add an additional square wave restoration output using one of these
https://www.newark.com/analog-devic...le-3-5ns/dp/28M3532?in_merch=Popular Products
as the devices rise time shoulders( knees?) due to capacitance driving issues it seems.

 

[atferrari]

Hola Mosaic,

Just in case, make sure that what you buy, if coming from China, is not one of the small boards where the manufacturer failed to implement the correct output filter.

In the quest of a sweeping DDS generator myself I read several comments as above, maybe related to the 5932.

What stops me is that the 5930 comes as SMT only.

Anyway, once I find a way to calculated the reccomended eliptic filter I will give a try.

Buena suerte.

 

[ronsimpson]

Notice the wave form looks bad near the maximum frequency.
The square wave has jitter because; there is a place to make a edge (positive or negative) every 25mhz. (40nS) If you want a 500khz square wave with edges every 1us things look good. If you want a edge every 1.001us things do not look so good. You will get edges at 1uS and 1.04uS with nothing in between. Looks like jitter.