Urgent Help

Thread Starter

diwa2000@gmail.com

Joined Apr 15, 2008
40
Help again.

I need to convert the AC signal at 433MHz to a clean DC signal such that I can input that to the microcontroller (PIC18F452) pin for further processing as the microcontroller understands dc signal. Im using a peak detector to do that. I wanted to know whether is there any module in the market which can achieve that ....or any other method other than peak detector that can achieve a clean DC.
This link gives the circuit that Im using http://www.arrl.org/tis/info/pdf/0706060.pdf

URGENT PLEASE HELP.

THANKS
DIWAKAR
 

beenthere

Joined Apr 20, 2004
15,819
If the 433 MHz signal is carrying information, it must be modulated. The ARRL peak detector (or envelope tracer) does a great job of demodulating AM. If it's just on/off, that method works fine, too.

The A to D converter can't run fast enough on any microprocessor to have aliasing problems with a trace of ripple at 433 MHz. If there is concern, do a full wave rectifier and take the ripple frequency up to 866 MHz.

If the A to D LSB sensitivity is 5 mv and the ripple is less than that, then it will not show up in the conversion. If you are still concerned, take several readings and average them.
 
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