ADAU196XAZ test, i can't get a digital input 24bit signal by the sigmastudio or the ARWB

HI

i bought the board EVAL-ADAU196XAZ, and want to get a pure analog output using this board.

the inportant thing is to generate a 24bit digital input signal, i see other DAC use the sigmastudio to program the board easily to get a input signal.

but in this board EVAL-ADAU196XAZ, when i use the sigmastudio, there is no schematic workspace, so can't add the input.

the ARWB can only control the register of the chip ADAU1966A, this software can't generate a 24bit digital input signal.

my question is how can we get a digital input to the EVAL-ADAU196XAZ, can ypu help provide some software to help generate the digital input?

thanks

Shangzheng

Parents
  • +1
    •  Analog Employees 
    on Feb 27, 2020 3:06 PM

    Hello Shangzheng,

    The SigmaStudio interface is only for controlling and setting the registers. Once all the settings are correct for your application it is easy to copy all the register settings so your system controller can properly program the part. This is the use of SigmaStudio with this part to give you real time control of the part.

    Audio has nothing to do with SigmaStudio. There is no way to get audio in or out. This is true even with a DSP.

    This evaluation board does not have an analog input. All the inputs are digital. The easiest way is to use an S/PDIF signal and send that to the board. There are provisions on the board to route this audio to all the outputs or only to selected outputs.

    The board can also be setup to receive an I2S or a TDM signal from some other digital source. This is often a DSP evaluation board. Do you have any of our DSP evaluation boards?

    I have also attached an updated user guide that is still a preliminary guide. It covers the old revision in the first half of the document and the new revision in the second half of the document.

    Dave T

    PDF

  • Hi Dave

    I am afraid i don't say clearly in the last reply,

    i am not trying to send ab audio signal, i am trying to use sigmastudio to create the code for high resolution sinewave that can be output from the ADAU1966A, the adau1966a is actually supposed to CREATE the audio frequency sinusoid(it is not an audio signal).

    1. i have the impression that i can use either sigmastudio(easiest) or the ARWB program (harder) to creat the digital code of a high quality 16/20/24 bit sinusoid@192/94/48Ksps and directly load this to the DAC via the little daughter card(connected to jumper J4 or whatever that interface to the PC)

    2. i don't want to have to load the digital signal through the external data ports.

    3. after configure well, i still unable to see the ADAU1966 DLL in sigmastudio, means there is no schematic workspace in this one, you can see last reply, so that i can't add the I/O, where are things break down, 

    4. finally, if this method isn't possible, if there is an available source of document to connect the matlab - as an alternative way of creating the digital representation of the sinusoid if it is not possible to do this using sigmastudio, or if this is easier than using the ARWB software.

    at last, if there is a newer version of the sigmastudio user's guide or document tation or an application note that might have an example that's fairly close to what i am trying to accomplish.

    thaks advancd

    Shangzheng

  • Hi Dave

    i have a small question about the adau1966a, the eval-adau196xaz.

    i can generate the output analog sinewave signal now, and i wonder if the eval-adau196xaz can have a dc voltage in the output, means i want the output sinewave have a dc voltage about 0.9v, 

    now, the scale of the output analog signal  is from -3.3v to 3.3v, means the dc is 0, how can i add a dc to this output sinewave?

    Thanks

    Shangzheng

  • 0
    •  Analog Employees 
    on Mar 6, 2020 2:11 PM in reply to 杨尚争

    Hello Shangzheng,

    The output of the DAC is actually riding up on the common mode voltage. The common mode voltage is around 1.5V. You can see this on your scope if you probe the SMT test points that are to the left of the output coupling caps. I circled them in this picture. On these test points you can get the raw output of the DACs that is riding up on the 1.5V common mode DC offset. Keep in mind that this is the raw unfiltered output so there is a lot of out-of-band energy in the signal at this point. 

    The schematic is in the user guide that I attached at the top of this post. 

    Having the common mode at 0.9V will mean that the signal will clip unsymmetrically. Which means it will clip on the bottom of the waveform sooner than the top. This will limit your max level before distortion. So I am not sure why you want it centered around 0.9V unless you are interfacing to a device that is using a 1.8V AVDD. 

    So you may need to do some level translation to match the common mode signal of 0.9V of the target device. 

    I will go into the shop and take a quick measurement of the ADAU1701 output for you. 

    Dave T

  • 0
    •  Analog Employees 
    on Mar 6, 2020 8:49 PM in reply to DaveThib

    Hello Shangzheng,

    I went into the lab and made some measurements. 

    See if this will meet your needs.

    Both of these were done with an internal oscillator set to -1dBFS

    This first one is the EVAL-ADAU1701MINI eval board.

    This one is the EVAL-ADAU1452RevBZ

    They both are pretty good. The ADAU1452 is using one of our popular codecs that was designed after the ADAU1701 was designed. The eval board already has all the connections you need. 

    By the way, going up in sample rate did not improve the distortion components you see. So unless you need to run that high there is no point in it for just producing a sine wave. Perhaps once you get up to 20kHz it would make a difference but at 1kHz it does not. 

    To modify the EVAL-ADAU1452RevBX to operate at higher sample rates will need some decent soldering skills and equipment. The instructions are in the user guide. The EVAL-ADAU1701 would require no modifications to run at higher rates. Just some settings in SigmaStudio.

    Dave T

  • Hi Dave

    Thanks a lot for your advice and help, all of them help a lot.

    i am going to consider about the board eval-adau1701 and eval-adau1452revbx. 

    sincerely

    Shangzheng

  • Hi Dave

    I see from the picture, the SFDR of the EVAL-ADAU1701MINI is 75dB and the EVAL-ADAU1452RevBZ is 85dB, we want to get a better signal like the SFDR higher than 90dB.

    I am afraid the amplifier limit the output analog signal of those two board, the amplifier after the DAC provide the drive ability to the output. i am not quiet sure about this. maybe the signal directly from the DSP is very good, and limit by the board DAC and the amplifier?

    and now, i want to buy one board 1701 or 1452, and i only want to use the DSP on the board,( because the dac on the board is worse than adau1966), and then send the digital signal direct to my board EVAL-ADAU196XAZ, which board is more easy to connect and more easy to program, i want a high quality digital signal from the DSP and then directly to EVAL-ADAU196XAZ, so that i can get a high quality analog output sinewave signal. which board is more suitable to buy? and i only want to use the DSP of the board.

    Thanks 

    Shangzheng

Reply
  • Hi Dave

    I see from the picture, the SFDR of the EVAL-ADAU1701MINI is 75dB and the EVAL-ADAU1452RevBZ is 85dB, we want to get a better signal like the SFDR higher than 90dB.

    I am afraid the amplifier limit the output analog signal of those two board, the amplifier after the DAC provide the drive ability to the output. i am not quiet sure about this. maybe the signal directly from the DSP is very good, and limit by the board DAC and the amplifier?

    and now, i want to buy one board 1701 or 1452, and i only want to use the DSP on the board,( because the dac on the board is worse than adau1966), and then send the digital signal direct to my board EVAL-ADAU196XAZ, which board is more easy to connect and more easy to program, i want a high quality digital signal from the DSP and then directly to EVAL-ADAU196XAZ, so that i can get a high quality analog output sinewave signal. which board is more suitable to buy? and i only want to use the DSP of the board.

    Thanks 

    Shangzheng

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