Why my mixer is not rectifying the signal?

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Anonymous
Not applicable

Hello everyone,

   

I have the following issue,

   

I am using a mixer in order to rectify the sine signal. But, the output is not rectified. In fact, it is just flipping (or just changing polarity).

   

I have the following configuration:

   

Mixer Input frequency: 50Khz

   

Mixer local oscillator input (LO): 50Khz coming from PWM.

   

Reference : Vdda/2 

   

Both signals are in phase, components are started correctly.

   

I don't really understand where the error lies.

   

Looking forward for your suggestions.

   

Regards

   

Awais

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1 Solution
rola_264706
Level 8
Level 8
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This mixer is working just as it should. When you apply two of the same frequencies to a mixer there is two outputs one is Upper Sideband and lower Sideband and  Image frequency in this case 0 as the two signals are the same frequency.

   

 

   

View solution in original post

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7 Replies
Anonymous
Not applicable

Why would a mixer rectify a signal ?

   

Please let us know what is mixed with what, what do you expect as result and what is the observed result ?

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Anonymous
Not applicable

Thank you for your reply.

   

I am trying to implement the following application note (see attachment).

   

and I am getting the result in the picture attached (Yellow wave is the input entering into the mixer and purple is the mixer output).

   

Looking forward for your suggestions.

   

Regards

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rola_264706
Level 8
Level 8
50 likes received 25 likes received 10 likes received

This mixer is working just as it should. When you apply two of the same frequencies to a mixer there is two outputs one is Upper Sideband and lower Sideband and  Image frequency in this case 0 as the two signals are the same frequency.

   

 

   

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rola_264706
Level 8
Level 8
50 likes received 25 likes received 10 likes received

Here is the configuration settings  for the mixer component.  As you can see I set the LO and the input to the same frequency and it warns that the output is a DC level of  0.

   

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Anonymous
Not applicable

Thank you for your reply.

   

I am trying to implement the following application note (see attachment).

   

and I am getting the result in the picture attached (Yellow wave is the input entering into the mixer and purple is the mixer output).

   

Looking forward for your suggestions.

   

Regards

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odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted
        Maknight, you must satisfy 2 conditions: mixer must be in multiplying mode and Vref must be exactly in the middle of input wave. Schematic example attached. P.S. It is wise to to post existing project for review.   

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gica_284176
Level 2
Level 2
Welcome! 10 replies posted 5 replies posted

To all

   

I very simple solution, that i use for a while, and work