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PCM3070 question in regard to GDE

KANJI SHIBATANI
Mastermind 6205 points
Other Parts Discussed in Thread: PCM3070

Hello

My customer is already using PCM3070 in their prpduct in the market ,  but intend to change the process flow on the GDE.

Here I send customer's question as attached  two files.

They are so hurried because they should release their firmware for consumer customer's update . 

 

Q1  Does the volume on Customer’s process flow can be changed in 0.5dB step?        

When we see the help window from volume’s property, it can be set 0.5dB step… 

Q2  Please let me the way to change  volume in 0.5dB step  in the GDE   as run-time property.       

My understanding is  0.5dB step in GDE  is NOT available; error message found.   

   ( 1dB  step is OK, it may be GDE’s issue..)  but please advise.    

  ( I and customer also tried to in Hex format in the property window, but        could not find the way.)

 


Q3  Please let us know the meaning of Q in the GDE’s  Equalizer( Q factor ) .

    I could not find any material in the GDE help window.     Easy to say, my understanding  is Q= f0/ Band width ( 3dB down), is it correct?
      
   Below ( attached ) is the AP result.  If Gain were 2.5dB, even though Q=0.9, it’s very broad.

    If Gain were 3.6dB ( =close to 3dB)  and Q= 0.9,  it seems sharper than Gain =4.8dB

 

Q4  Treble shelf in + xx dB have offset.   Is it make sense?   Please advise.

 

 

  • 0
    TI__Mastermind 27990 points
    Hi Kanji,

    I am looking into this and will get back to you by Thursday this week.

    Justin
  • 0 in reply to Justin Bohr
    TI__Guru* 84915 points

    Hi, Kanji,

    I apologize for the late response.

    Q1  Does the volume on Customer’s process flow can be changed in 0.5dB step?

    I think that the help window has a mistake on the accepted volume values. The volume block cannot be changed in 0.5dB steps. I tried with different EVMs and the volume block shows an error when the volume is not configured as an integer. This block only accepts integer values from (-110dB to 6dB).

    Q2  Please let me the way to change  volume in 0.5dB step  in the GDE   as run-time property.


    As I already explained in Q1, the volume cannot be changed in 0.5dB. However, if you want to change the volume in GDE as run-time property, you must configure the miniDSP_A and miniDSP_D in adaptive mode.

    Q3  Please let us know the meaning of Q in the GDE’s  Equalizer( Q factor ) .


    The Q factor is the relationship between cut-off frequency and bandwidth at 3dB down as you already mentioned (Q = fc/BW). I noticed that in your first graph, you configured Q as 0.9 and 0.4. However, the correct range is from 1 to 10. Probably, there are some discrepancies in your example because Q is not in the correct range.

    Q4  Treble shelf in + xx dB have offset.   Is it make sense?   Please advise.


    Ideal filters are shown in the following pictures:

    • Treble shelf filter, fc = 1000Hz, 6dB.

    • Treble shelf filter, fc = 1000Hz, -6dB.

    In your second graph, it seems that there are an additional high-pass filter added to the shelf filter. So, the real filter could show some differences such gain or phase. So, it make sense.

    I hope this helps you. Please let me know if you have more questions or comments.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Mastermind 6205 points

    Dear  Luis-san,

    Thank you for your answer !!

    I understood about Q1~ Q4.

    Please allow me to have a question in addition to Q1.

    Q5

    My understanding  is following.

    Easy to say, customer can set volume in the 0.5dB step from  the GDE i2c memory tool.

    Is it correct ?

    Please advise.

    ( I 'm sorry that I  did not check in the EVM  because  I don't  have AP just now..) 

    ~~~~~~~~~~~~

     The volume component can not be set  as 0.5dB step in the GDE run-time  property,

     but,  via following step,  customer can  set 0.5dB step in the GDE.

    * 1  check the  page and i2c address from  component interface overview window

    * 2  tools=> i2c memory tool => i2c read/write

    *3    write the  HEX value to the its page and  i2c address directly   in 0.5dB step.

  • 0 in reply to KANJI SHIBATANI
    TI__Guru* 84915 points

    Hello, Shibatani-San,

    That's correct. I could change the volume in 0.5dB steps with the I2C memory tool as customer mentioned. Probably, the GDE doesn't accept these values but the miniDSP can change the volume in 0.5dB steps as the Volume help window explains.

    Volume.pdf

    Best regards,
    Luis Fernando Rodríguez S.