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ADL5511-evalz not giving correct envelope

Question asked by Coolguy2k17 on Jul 27, 2017
Latest reply on Aug 8, 2017 by Coolguy2k17

Hi,

I recently got the ADL5511 evaluation board and want to do the envelope detection for 3.2 GHz carrier wave modulated by 100 kHz sinusoidal / sawtooth signal.

 

I did not make any changes to the board and connected RF (3.2 GHz) from antenna to board's input port and VENV to oscilloscope.

 

Biasing is at 5 V and switch ON. The current drawn at ON position is 22mA.

 

On the oscilloscope, I am not getting the 100 KHz envelope. The signal seems to be only showing positive peaks where negative of the baseband signal should be. 

 

On the Oscilloscope (please see pics) the top plot is modulating 100 KHz signal (CH1) and bottom one is output from the ADL5511 board (CH2).

 

As we can see that the two signals are different where board output seems to be flipped at negative of modulating signal (CH2 shows twice the frequency wrt CH1).

 

I have attached some pictures so that you can have a look. Please let me know how can I get the correct baseband signal with this kit. Thank you.

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