ADSP-SC589_EZ-Board Analog input noise

I have a ADSP-SC589_EZ-Board, and I am using it with SigmaStudio for SHARC 4.6 and CCES 2.10.0, Windows 10.

I notice that I get a 3kHz noise signal with harmonics when I connect a source with a finite output impedance. In fact, as soon as I connect a dummy source (simply a connector with an impedance of 600 Ohms between pin and GND) to the analog inout I get this noise signal.  The signal level is equivalent to 1mV p-p. This gives me a maximum S/N ratio of 50dB, which is not impressive, and it is not enough for my application as it is very specific and clearly audible. White noise would have been more acceptable.

Is this known, or is there something wrong with my EZ board?

Is there any way I can improve the situation?

BN



correction of misspell
[edited by: bnilsson at 3:23 PM (GMT -4) on 20 Sep 2021]
  • Some time have passed now, I wonder if I can expect any answers or suggestions from your team?

    /BN

  • Did you run all of the Power On Self Tests on this board? And did they all pass?

    -Matt

  • I could not do all tests, since I lack the necessary cables.

    Standard loop test passed.

    LED test "passed", but.no LED10/11/12 activity.

    UART test passed

    HADC test passed.

    CAN not performed, no cable.

    SPDIF coax test passed.

    SD card test passed.

    INA3221 test failed:

    INA3221 Chan 1 single shunt voltage 33760uV not in range

    INA3221 Chan 1 continuous shunt voltage 33360uV not in range

    INA3221 Chan 1 continuous shunt voltage 33240uV not in range

    Si5356A Clk Gen: passed 1  failed 0

    SPI EEPROM Test passed

    ADC/DAC RED Channels  !!!!!FAILED!!!!!FAILED!!!!!Failed channel: 3

    SPI Flash Test passed

    Firmware test passed

    Firmware version: 1.0
    Built on Sep 20 2021, at 19:54:48

    ETHERNET_100MBPS no cable
    ETHERNET_BRD_TO_BRD_CONT no cable, no 2nd board
    ETHERNET_BRD_TO_BRD no cable, no 2nd board

    ADC/DAC WHITE Channels  !!!!!FAILED!!!!!FAILED!!!!!Failed channel: 0

    Loop flag test passed.

    I have to say it is difficult to decode the picture of the analog ADC/DAC test cables. Are really two DAC outputs connected together and then going in to a ADC input? I find this highly unusual. Anyway, I tried to make the analog test cables as I understand the picture, but the ADC/DAC tests all failed.

    /BN