Is there an if statement in ADAU1701?

Hello frenzyhasaki,

You need to use an index selectable filter. There are many ways to setup how the indexes are developed. This one way simply uses a pot connected to the AUXADC input but this is not exactly what you need to do. Have a look at it anyway to learn a little more about SigmaStudio programming.

https://ez.analog.com/message/18475?commentID=18475#comment-18475

This post is similar and has a small program I wrote that shows how to use a lookup table.

https://ez.analog.com/message/268779-re-adau-1701?commentID=268779#comment-268779

What you will need to do is use an envelope generator to create a DC level from the audio. Then feed that into a lookup table that will then select the filter number based on the audio input.

I thought there was a project on the forum showing this but I could not find it late this evening.

Have a look around the forum and keep asking questions. Others may chime in and offer other suggestions.

Dave T

Dave and frenzyhasaki,

I managed to find one of my old projects which uses an envelope follower and lookup tables to control index filters:

Dynamic loudness in 1701

(Please scroll down one post below the top one to find the correct example).

Best regards,

Bob

Thank you Dave! Sorry for my late reply.

I'm doing multiple filters and then use the index selectable multiplexer to select filter, instead of using ISF because:

1. I'm working on a hearing aid that auto fits the sound loudness of the enviornment

2. Filters should be with multiple band, and ISF doesn't allow me to (or I haven't found out how to) use multiple band pass filters

Thanks for your advice of using the envelope. It should be useful when I figure out how to use the LUT to control the multiplexer.

Best,

Joseph