RMS value to analog output pin
Hi everyone,
I'm using the EVAL-ADAU1467Z board and my project concerns the use of the function "Level Detectors". Specifically, I am using the "RTA to Output" which outputs the RMS value. This RMS value is Analog, but it is not an Audio signal.
I learned that the RMS value can be read by "DSP Readback" block.
My question is whether it is possible to connect,inside SigmaStudio Schematic, the RMS (red pin) to an analogue output (of the AD1937, I suppose) in order to read the RMS value as a voltage on a multipurpose (hardware) pin.
Thank you!
Integrated/Special Purpose A/D Converters
Audio CODECs
ad1937
Absolutely you can! I just tried it on my ADAU1466 eval board. Connecting a DC Source to the I2S output to the on-board AD1938 codec, I got these measurements:
DC Src Output:
-1 0.28
-0.5 0.90
0 1.53
0.5 2.15
1 2.77
If your micro runs on 3.3V these values are ideal for its ADC. The codec is designed for audio, not for instrumentation -- so I suggest you have your micro run a sort of auto-cal scheme at power-up -- where it puts known input(s) through the DAC and notes the results. On a mixer we produced, we found that a simple one-point cal at the bottom end of the level scale (where accuracy is important in dB terms) was sufficient.
Best regards,
Bob
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