Sine wave generator up to 150 MHz

Projects General Guidance
1

Hi everyone,

I was wondering if it's possible to create a sine wave of selectable frequency, up to about 150 MHz.
I know that with arduino alone it's impossible, but with DDS modules is easier.
I've found on ebay an ad9850, but it seems to work good only up to 40 MHz. I cannot find any other module (obviously i can't buy a dds chip alone, I need the module for the connection with arduino)...
Do you know if exists something like that and where to buy it?

Also any other idea/advice is fine :wink:

Thank you

2

Look at the ham radio sites for designs of frequency synthesisers. Not sure what the. Arduino has to play in this project though.

3

How about something like this:

What kind of test equipment do you have that will tell you its working?

4

@grumpy_mike: I thought about arduino because in a lot of projects arduino is used to control ad9850 module, and I want to keep it simple and portable..

@crossroads: It seems a good idea, but i was wondering if it's possible to do it without a lot of wiring, etc..

as you can see here Testing an eBay AD9850 DDS module with Arduino Uno | NR8O
only arduino, the module, and the sine wave output :slight_smile: I'd like something like this...
You think that it's impossible to do?

5

Maybe use the ad9850 as the input to the higher frequeny PLL, let it multiply the frequency up for you. You'd have to search around to find one mounted on a board already.

6

Yes, good idea!! thanks, I will think about it..
And to reply to your previous question, no problem for the testing equipment :wink: in my office we have everything!

7

While a PLL will get you to the frequency you want do you have any specifications on what phase jitter performance you need?

8

We have a simple measurement setup with a tx and a rx to test some metal shields.
Now we are using a huge function generator, but it's too much for us, since we need only a sine wave at fixed frequencies...
There are no specifications on the phase of the signal, we perform simple tests, we only need that the spectral component at the desidered frequency is stable.

9

Hi, this youtube shows the ad9850 being used with the arduino, unfortunately only at 7Mhz.

www.ad7c.com/projects/ad9850-dds-vfo/

Is the creators site, the AD9850 is serially addressed and as shown with Arduino and LCD display is quite a compact but powerful assembly.
Makes stable VFO's possible without the old analog circuit problems.

I have a ad9850 with breakout and hope to play with it over Christmas.
So as suggested a doubling circuit or PLL.
The clock frequency of the DDS sets the output freq, so you would be looking for a DDS clock with 500MHz.

Tom..... :slight_smile:

10

thanks for your post Tom.

Yes, I knew about ad9850, but as I said in the first post, it works only at "low" frequencies.

So, as you guys said, I've to find some pll circuit...
Or a high frequency clock DDS, already mounted on a module, but I wasn't able to find one yet..

11

The AD9850 is the oldest and obsolete one.
There are DDS chips from Analog Devices up to 500MHz sinus output (1GHz master clock).
For 150MHz output you need 300-500MHz master clock models.
See:

You may try with si570 (10MHz - 1.4GHz output, lot of models) from Silicon Labs, not with sinus output, but easy to use. You need a good low pass filter at the output, however.

12

thanks also to you pito!

the only problem is to find a chip already mounted on a module, to minimize wiring and soldering.
I will take a look at the models you suggested..

13

Maybe im a bit late on this reply but SI got developmant boards like this one.
http://www.silabs.com/products/clocksoscillators/pages/si570-prog-evb.aspx