NooElec AD9850 DDS Signal/Function Generator Module, Digital Tester

I purchased these to use as a VFO for a radio I was building. They work very well. google DDS signal generator for hookup and Arduino code. There are no directions with these units. With the 125 MHz oscillator, they can go up to about 60 MHz but the signal is not clean. Keep the frequency below about 30 MHz and it will look good. The output does drop off as the frequency get higher. You may need an amplifier for some applications. I had to adjust the pot before there was any output on the square wave pins. The sine wave pins work with no adjustment of the pot. The pot only needs adjust if you want to use the square wave output.

I paid the extra $11 thinking I would get the unit pictured in the description with the better quality Clock Crystal.I didn't.

No documentation whatsoever is included. This seller makes no representation of specs or anything, so you have to trust that this is the same circuit that other sellers have, which are all derived from the AD9850 data sheets. The module I received was missing a smt inductor which prevented square wave outputs. Nothing had ever been soldered where the part should have been so I imagine there is little or no QC that allowed the mistake to pass. The seller quickly shipped a replacement that is good. The AD9850 part itself is rated for 5 or 3.3 volt operation, but these modules should run at only 5 volts because they use a 125mHz clock. AD9850 is only rated to accept up to a 110mHz clock at 3.3 volts. At 3.3 volts, mine was not useable. Works fine at 5 volts albeit power hungry at 112ma.

I already expected that no documentation would be supplied with this part, but there is plenty on info online. This was the closest product to match what I wanted, and after replacing the 125MHz clock oscillator with a 4MHz one, I have a very accurate programmable square wave generator that gives me the frequencies that I want. (0 - 1MHz). Great product that saved me my time, money, and the inconvenience of putting something like this together from scratch.

They must not test these devices before shipping them

Unbelievable there could be a signal generator with this level of accuracy and speed at this price and small size! I believe it can be used to trigger a pulsed laser as well (which is my application). Will create sine and square waves. Square waves (TTL) can be used to trigger a pulsed laser. I think also possible to replace the trim pot with a connection to a digital pot and control more aspects of the device through a microcontroller (such as Arduino, etc.).

It worked however the led did not light up. Replaced led and then it was ok

This module works well. I wired it up to an Arduino and used the appropriate library. Output was on frequency, but signal level varied with frequency, dropping at higher frequencies (as you might expect). You can software trim it for exact output frequency if you have a standard (or can zero beat it with WWV).