Monday, 28 November 2016

4.4GHz Signal Generator - Really?

Well,

I attended the GMRT event this year, one of the highlights was seeing this in the flesh:


I also spotted a great project by GM8BJF which was a great signal generator covering 35MHz up to 4.4GHz using very cheap Chinese and eBay sourced components.

Here are the bits, firstly a ADF4351 evaluation board:

 


Secondly, a CY7C68013A development board:



And finally a broadband amp module:



Total cost of these three modules delivered was less than 45 GBP.

Now, I've tried two ways to drive the ADF4351, firstly using some excellent software from F1CJN - this worked very well and would make an excellent stand alone sig gen.

However, I have decided to replicate the project by GM8BJF exactly and use the three boards above together.

I followed the instructions on his website and have programmed the EEPROM on the CY7C68013A board and am now using the software from Analogue Devices from my PC to set the output frequency:




This software controls the ADF4351 from a PC using a USB connection and allows you to see all the register values and fiddle with all the device config - most excellent!

Here's a quick shot of the spectrum analyser connected to the output with the device set to 1.2GHz:


This is an appalling picture of the boards under test:


And here, Miss Florrie Cat assisting:

Neat, egh?


4 comments:

  1. Replies
    1. She is almost always nearly entirely in the way!

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  2. Hi I am using this sig gen in my prject. But i observed lot of people complaining about lot of harmonics at lower frequencies giving almost a square wave. Did you also come across similar thing? I understand that it's not a concern at higher freqs. but asking just in case you observed this.

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    Replies
    1. Yes, the frequency generated is a square wave below 2.2GHz (I think) so you need to filter it.

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