how to understand level detector value

UP！

Hello

I'm very eager to know how to read the level value. Project is hold on. Please help. Thanks in advance!

BR,

Jackie

https://ez.analog.com/message/5354#5354

Hi Jackie:

The values you mention are only for controlling the time constants of the envelope being created to monitor the signal when using the level detectors. I believe you are looking to understand how to read back from the DSP to monitor for the signal level. If so, please follow the instructions provided on the above link.

Please comment.

Miguel

Thanks Miguel.

Now I can understand how to readback the level of a single detector, such as a RMS detector.

But I still can not readback 7 values from the 7-band detector. The readback control only give me one value. How should I do? Thanks,

BR.,

Jackie

Jackie,

Please use the parameters window to check where the 7 parameters are stored in memory. You can find a guide to using the parameters window here: http://videos.analog.com/video/products/audiovideo-products/756712925001/SigmaStudio-C3-Parameters-Window/

Hi Brett,

I attached 2 screen snaps here. Please help to indicate which addresses store SingleBand and SevenBand value. Thank you.

Please do not spend your time at this moment. I will try to build envelope and readback unit. Will back here with result.

Thank you.

Done!!

But I find that all addresses of ReadBack are same. Only the initial value are different.

I will use uC to read 0x081A, how to do 'Read Init' and read 'Result' ?

I feel I am very near to the target! Thank you!

Jackie

Hi Jackie:

Have you looking into the comiled generated files. There should be one file that shows all addresses for readback modules present in the schematic, including the Level Detectors. I don't remember exactly but believe it's spi_map.dat. Please look at those files, you will find all the addresses that you need to read back from.

Regards

Miguel

Hi Jackie,

Please look at this FAQ to learn how to use the DSP Readback cells: https://ez.analog.com/docs/DOC-3130

You can also follow this FAQ to create your own level detectors, instead of using the default level detector in SigmaStudio's library: https://ez.analog.com/message/7669#7669

Hi Brett,

Just read this thread and the FAQ link and found them very helpful for my current project. However, as I was about to code it up in my micro app, I noticed the decay value is somewhat of a mystery to me. I have tried various means of obtaining the number that is output from the Sigma app to no avail. The Sigma schematic shows decay as "k/s" but the help file shows "dB/s". Could you lend me some insight into what these units really are?

Thanks

Chuck,

Happy New Year!

Sorry that I missed this post of yours last month.

The k/s decay parameter is actually a linear decay, as described by KJBob here: https://ez.analog.com/message/128220#128220

There is a clever workaround to make an exponential decay at the cost of a few more instructions, described here: https://ez.analog.com/message/64597#64597

We plan to make a real exponential decay in the library sometime in the future.

I hope this answers your question adequately.

Thanks,

Brett

Hello Chuck,

The Mg block is the Signal Merger. It takes the average of its inputs (adds them together and divides by the number of inputs). Thus, the two-input version has a built-in 6 dB loss. This prevents overloading when a number of full-scale inputs are mixed together.

Bob

Brett

Thanks for the reply. It was very helpful.

But I have new questions now. Trying to use the real-time display graph.

As a test I used an AB/CD type comparator and several DC sources for I/O

and thresholds. Also used pink noise, square wave and sine wave for

sources, with gain, and fed the results into both the Graph display and

the level meter. Compiles fine, downloads fine... graphs do not react as

expected.

Also, I'm using WIn7 on an i7 CPU with 16GB ram.

What am I missing? Shouldn't I be able to make the schematic work by

itself without passing audio through the eval board?

Hope you can help.

chuck

Oh, BTW, I have been attempting to recreate the schematic shown listed

in the 2nd link below. There is a block labeled Mg1 right at the input

which I can't identify. It has 2 in, 1 out... looks like maybe a

Magnitude block, or a shelving filter... but I can't seem to find it in

the Toolbox. Do you know what it is?

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