Purpose of AI Stimulus input in NI Sound and Vibration toolkit

[EDGAR_PLATRONICS]

Hello:

I am working in an application to generate multi tone audio in a speaker and at the same time read signal in a Microphone by using cDAQ

Also I am using NI Sound and Vibration toolkit.

This program is working but most of examples I found in this toolkit have 2 channel inputs and 1 output as next:

AO Source

AI Stimulus

AI Response

I already connected speaker to AO source (including and audio amplifier) and connected Microphone to AI Response.

In case of AI Stimulus, I selected one channel not in use and do not connect anything.

Application is now working, I generate audio and read signal but what is the purpose of AI Stimulus input?

What if I have no signal to wire it?

What can connect to this input?

Regards

[djac91]

Generally in sound and vibration applications, a device or system under test (DUT) is excited with a signal and the response is acquired along with the original signal (stimulus). For example to perform frequency response analysis and calculate gain, phase and plot bode we need to acquire the response from the system as well as the input given to the system using AO from our daq card. In other words stimulus is actually a loop-back connection from the AO channel. . Have a look at the picture below

[EDGAR_PLATRONICS]

Thank you