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TLV320AIC3104EVM-K: Generate Audio Profile ranging from -10 dB HL to 120 dB HL

Aditya Padekallu
Prodigy 60 points
Part Number: TLV320AIC3104EVM-K


Tool/software:

Hi,

We are working on a project where we want to achieve a volume level in the range of -10 dB HL to 120 dB HL with a step size of 5 dB. In the EVM software, there are several negative values in the DAC_L and DAC_R sections of the GUI. I have attached an image which shows these negative values. There is no unit specified for the values in the column, which creates confusion in identifying whether I am working with dB SPL or dB HL.

Another problem I am facing is that I am getting ~ 25 to 30 dB SPL (measured in HIT box) at -78.3 value in the column, which seems to be the last value in the column. Is there any way in which I can program the codec to give an audio profile ranging from -10 dB HL to 120 dB HL? 

DAC_VALUES

  • +1
    TI__Genius 14555 points

    Hi,

    Those drop downs are controlling output volume control - so it would be dB in reference to the full scale output level. There is also the "volume" dropdown next to the line out DAC volume control - that would be output gain, which can range from +0 to +9 dB. So, there is a volume control from 0 to -78.3dB, and then a gain stage from 0 to +9dB. Mapping these output levels to dB HL would depend on your speaker amplifier as well - this volume affects the low voltage analog output from the DAC. If you want a bigger dB range of output, you would need to amplify the signal further. The idea of these output levels is that if the gain is set to 0dB and the volume is set to 0dB of attenuation, a full scale digital signal should be 1.414Vrms as shown in the datasheet here:

    This means that if your digital volume is set to -6dB then we will see a halving of the output voltage.

    We can also see here in the datasheet that the dynamic range is nominally 97dB - so 130dB of dynamic range will not be possible with this device, as the noise floor will be hit before you get to -130dB from full scale. You will need to design your system with this in mind.

    Let me know if you have more questions.

    Best,
    Mir