This thing does what it's supposed to. It's actually relatively one of the easier chips to talk to as well. I've worked with some other time generation chips that require more complicated command structures involving choosing an octave, then a frequency within that octave and then phase and proper command to engage. All this requires is a frequency represented by a 32bit unsigned integer scaled from 0Hz to 125Hz. Phase is optional and only really useful if you have two or more of these things, or want to lag the signal behind the reference crystal. This thing can be talked to in serial or parallel. Serial is what I did. Note: to have to hard wire a couple of the data pins to Vcc and others to GND to get the roper behavior..info is in the data sheet.
There's no documentation for this thing, but it's basically a breakout board for the AD9850, the data sheet will get you far, you just need to figure out the breakout pins to the chip pins. The chip has a built in comparator (for square wave generation), the threshold voltage is controlled by the trim-pot on the board (I could find no mention of this anywhere); the board feeds its generated sine wave to the comparator already.
Buy it with
This item: Puuli AD9850 DDS Signal Generator Module 0-40MHz IC Test Equipment AD9850
$29.95
Get it as soon as Thursday, Oct 10
Only 6 left in stock - order soon.
+
$339.00
Get it as soon as Friday, Oct 11
In Stock
+
$24.40
Sold by Envistia Mall and ships from Amazon Fulfillment.
Total price: $00
To see our price, add these items to your cart.
Choose items to buy together.
Customers also viewed these products
Page 1 of 1 Start overPage 1 of 1
Despite the documentation I had fun with this device!
I'm giving this device 3 stars due to the inadequate nature of the documentation available for it. There are numerous typos and lack of information that would make anyone not familiar with RF circuitry and design believe the device is defective. That said, here are my observations. There are two sine wave output pins Sine Wave Output1 (pin 9) and Sine Wave Output2 (pin10). Of course both are labelled Sine Wave Output1. Be that as it may, pin 9 is the "raw" output from the DDS terminated at 100 ohms. Pin 10 is described as the complimentary output; however, and this is where confusion lies, it is actually going through an 8 pole Butterworth filter with a 3 dB cutoff at 21 MHz and should be labelled "filtered" output. The output rolls off -25 dB/ decade so don't expect to get much signal above 20 MHz at this pin. Pin 9 will give a decent output all the way to 40 MHz with less than 3 dB attenuation at 40 KHz. I intend to run that output through a limiter to keep the signal at 500 mv p-p and amplify it to 2 v p-p into a 50 ohm load. One thing to consider, you can get the output past 40 MHz but as you approach the Nyquist frequency (.5 the clock frequency) you start to run into aliasing issues. The output looks like it's amplitude modulated at 55 MHz. I've included screen caps of the data I've collected for this board. All my measurements were made using a Hantek 75 MHz sampling O'Scope, 10:1 probe directly to the DDS header, and an Arduino Uno with the DDS mounted on a custom shield. In conclusion, this device is worth the price despite the dodgy documentation. However, don't expect to use it without some support circuitry.
