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signal merger attenuation

Category: Software
Product Number: ADAU1401

Hello All,

I'm searching for information for signal merger on the forum, and have som confusion.

Difference between NxM mixer and signal add - Q&A - SigmaDSP Processors & SigmaStudio Dev. Tool - EngineerZone (

in this post, it mentioned that Only the Signal Merger's output was at the same level as the input, no gain.

However, in another post Signal merge - Q&A - SigmaDSP Processors & SigmaStudio Dev. Tool - EngineerZone (

The Signal Merger is designed to attenuate according to how many input pins it's been grown to.  A two-input merger has a gain of 1/2 (-6 dB), a three-input merger, 1/3 (-9.5 dB), a four-input merger, 1/4 (-12 dB), and so on.

So i was wondering if there was something wrong with my understanding? 

Could anyone help to make a clarification. 


Best Regards.


  • and i built an example project for verifcation, actually the signal merger's output was the same as the input, no gain.

    So how can i get anttenuation via signal merger?

  • Hello Eason,

    By the way, Thanks for using your name. I much rather be more personal than a user name. 

    You actually proved the Sigma Merger reduces the level by 6dB

    You are adding together two exactly correlated signals which means the addition of the two signals will be twice the voltage which is +6dB. 

    The fact that you still see the same level means the signal output was reduced by 6dB. The merger will add the two inputs and reduce it by 6dB. 

    Look at this comparison I did where the two signals are simply added. The result is a 6dB gain as compared to the Merger output that was reduced by 6dB. 

    Dave T

  • Hello Dave,

    Thanks for your detailed explaination. I got your point. 

    if Adding two signals, the output should be increased. after the signal merger, the output is reduced. that's correct.

    Thanks again for your support.