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| AD9850 Pin connections |
Direct digital synthesis of RF signals using a cheap AD9850 ebay module is getting very popular. These modules needs a 40 bit tuning/frequency (and phase) data which needs to be inputted in to the module by a microcontroller/PIC/Arduino. Often it is useful to run these cheap modules to replace Crystal oscillators and running at a fixed frequency. It is possible to achieve this with an inexpensive decade counter (4017) and a couple of electronic components. The frequency setting is done with 4 DIP switches which can be used to set the 32bit frequency information by toggling the switches. Go to http://designtools.analog.com/dtDDSWeb/dtDDSMain.aspx to calculate the switch settings for the desired frequency
The original idea is from
Han Summers, G0UPL
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| AD9850 - DDS without using a microcontroller (click to see the full circuit) |
wow ! iam also working on that. vu3inj.blogspot.in thanks riyas. de vu3inj. indrajitsinh.
ReplyDeleteThanks for the comment. Here 74HC04 act as a clock generator and triggres 74HC4017. The output of 4017 goes high in a sequential manner from Q0... Q4 pushing 5bytes of data (first being phase info, so we dont set it with DIP switch). When Q5 goes up it signals the frequency update pin of dds. So this is a 'modified' led chaser circuit which you might have made years ago :) [with 555 and CD4017]
DeleteThis is interesting as I would like this module to be on a fixed frequency to eliminate programming with arduino.Less code to mess with the better.However,will it work as an rf transmitter this way,if so,where on the diagram is RF output?
ReplyDeleterf is on the sine wave pins.
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