1701 auto mute

Hello PowerPan, All assigned engineers are out of office currently. DaveThib will be back in the week of 1/5/2026 to answer your question!

ADI North America will be on winter shutdown starting December 24, 2024; perhaps another community member can assist you until our return on January 2, 2025.

Hello Power Pan,

If I understand correctly, you would like to have the Signal Detect mute the -1701's output at no-signal conditions. The Signal Detect block outputs a high level (1.00 in 5.23 format) when no signal is detected, and zero otherwise. Yet, as you said it cannot mute the audio on its own, it needs a control element. One method is shown below:

The DC Block filter removes any DC at the input. Sigma-delta ADCs often add a small DC offset to the input audio -- at about -45 dB it's enough to fake out your level detector, making the DC block necessary. The Zero Comparator block inverts the Flag Output to drive the Volume Control ON when the signal is present. DACs 2 and 3 drive the headphone jack on my ADAU1701MINIZ eval board; set the Output blocks to match your hardware.

Auto-Mute.dspproj

Some designers instead run the Signal Detect flag out to a GPIO to control a power amp; this is another possibility.

Best regards,

Bob

Hello Bob

Thanks for your prompt reply. The above project works very well. And I tried that the input of SW vol 0x800000(tested by sources->DC input entry) is 0db as volume control. tried for hours and solved the problem.

Best regards,

Power Pan