How to terminate an unused input in SigmaStudio schematic

manuelkw Question

Oct 26, 2015 00:00

Hi,

I am working in designing a schematic in Sigmastudio based on ADAU1761. There are some components needing several inputs for working, however, if we are just using part of its functions, then some inputs are not used actually in the real application. We cannot leave them open as it will become error but we cannot know how to connect them or terminate them in a proper way.

One practical example is that we are using a Combo Peak/RMS Compressor (from Dynamic Processor->Combo : RMS + peak --> Mono --> PeakRMSCombo(no gain)). There is an input pin at the left side (Ext Detect), but in our application, we do not use it. When we leave it opened, it cannot compile successfully. We do not know what parts/components should be connected to it.

Please help.

thanks & regards,

manuel

Audio Signal Processors

SigmaDSP Audio Processors

adau1761

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joe42 Reply

Nov 23, 2015 00:00

You can feed it a DC input, or (perhaps more efficient) just split the signal from the other input.

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DaveThib Reply

Nov 30, 2015 00:00

Hello Manuel,

In the case of the dynamic processor you selected, this is the external detector input. This input is what feeds the side-chain signal detectors in the compressor. If you do not send in a signal then there will be no compression. Some compressors will send the input signal to the detectors but in this case it is brought out as a separate input to give you flexibility on what you send to the detector.

So you need to "T" the input signal and send it to the external detector input pin. Then it will operate as you expect.

This is often used to create a de-esser circuit to reduce the "S" sounds in speech by taking the input signal and running it through an equalizer that is set to accentuate the "S" sound. Then feed that signal into the external detector and you will attenuate the "S" sounds much more than the rest of the audio.

Dave T

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EZAdministrator Reply

Aug 2, 2018 00:00

This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,
EZ Admin

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