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TLV320AIC3101: Recording sound breakiing up issue

Hello,

Record with a fixed gain using a microphone.
Recording Sound is breakiing up.

Breaking up is proportional to PGA gain. It occurs from over 50dB.
Breaking up relation to Sampring rate.
Breaking up lengths and intervals are random.

Registers used (excluding sampling frequency)

Register 25: MICBIAS 0X40 2.0V
Register 42: Output Driver Pop Reduction 0X50 Driver power-on time = 50msec
Register 12: Audio Codec Digital Filter 0XA0 ADC high-pass filter -3-dB

Register 15: Left-ADC PGA Gain 0X77 gain = 59.5 dB
Register 16: Right-ADC PGA Gain 0X77 gain = 59.5 dB

Register 26: Left-AGC Control 0X00 Left AGC is disabled.
Register 29: Right-AGC Control 0X00 Right AGC is disabled.
Register 27: Left-AGC Control 0X00 gain = 0 dB
Register 30: Right-AGC Control 0X00 gain = 0 dB
Register 32: Left-AGC Gain 0XE8 gain = -12 dB
Register 33: Right-AGC Gain 0XE8 gain = -12 dB

Register 19: MIC1LP/LINE1LP to Left-ADC 0X7C LINE1L is not connected to the left-ADC PGA. LADC_CPC
Register 22: MIC1RP/LINE1RP to Right-ADC 0X7C LINE1R is not connected to the right-ADC PGA. RADC_CPC

Register 17: MIC2L/R to Left-ADC 0X0F Input level = 0 dB, MIC2R/LINE2R is not connected to the left-ADC PGA.
Register 18: MIC2/LINE2 to Right-ADC 0XF0 Input level = 0 dB, MIC2R/LINE2R is not connected to the right-ADC PGA.


Best Regards,

  • Hi,

    Which path and which output driver are you enabling and is it only happened at ADC gain 50dB and above?

    Is this MIC3 straight to output or is it going through the ADC-DAC?

    Is the input or output clipping in this condition? From the above registers it looks ok and if it's ok below 50dB then it looks like clipping issue.

    You might need to check the input/output waveform.

    Regards.

  • Hi,

    a lot of thanks.

    > Which path and which output driver are you enabling and is it only happened at ADC gain 50dB and above?

    No output. DAC is off. For now, it occurs above 50 dB. However, we have not confirmed it in 0.5dB steps.

    > Is this MIC3 straight to output or is it going through the ADC-DAC?

    No. Only record.

    > Is the input or output clipping in this condition?

    As far as I can see the recorded waveform, I don't think it has been clipped.
    It is a recording of only environmental noise.

    Best regards,

    Kaz

  • Hi,

    OK, so the path is from MIC3 to I2S and only occurs at ADC gain above 50dB setting.

    Can you send me the full register configuration and what is your MCLK frequency?

    Is the MIC3 input level constant, what if you send 1 KHz tone at fix level?

    Regards,

    Peter

  • MCLK 12MHz

    PAGE0 Register dump

    [0] 0 (0x0)
    [1] 0 (0x0)
    [2] 0 (0x0)
    [3] 193 (0xC1)
    [4] 28 (0x1C)
    [5] 82 (0x52)
    [6] 64 (0x40)
    [7] 0 (0x0)
    [8] 208 (0xD0)
    [9] 48 (0x30)
    [10] 0 (0x0)
    [11] 193 (0xC1)
    [12] 160 (0xA0)
    [13] 0 (0x0)
    [14] 0 (0x0)
    [15] 119 (0x77)
    [16] 119 (0x77)
    [17] 15 (0xF)
    [18] 240 (0xF0)
    [19] 124 (0x7C)
    [20] 120 (0x78)
    [21] 120 (0x78)
    [22] 124 (0x7C)
    [23] 120 (0x78)
    [24] 120 (0x78)
    [25] 70 (0x46)
    [26] 0 (0x0)
    [27] 0 (0x0)
    [28] 0 (0x0)
    [29] 0 (0x0)
    [30] 0 (0x0)
    [31] 0 (0x0)
    [32] 0 (0x0)
    [33] 0 (0x0)
    [34] 0 (0x0)
    [35] 0 (0x0)
    [36] 204 (0xCC)
    [37] 0 (0x0)
    [38] 0 (0x0)
    [39] 0 (0x0)
    [40] 0 (0x0)
    [41] 0 (0x0)
    [42] 88 (0x58)
    [43] 128 (0x80)
    [44] 128 (0x80)
    [45] 0 (0x0)
    [46] 0 (0x0)
    [47] 0 (0x0)
    [48] 0 (0x0)
    [49] 0 (0x0)
    [50] 0 (0x0)
    [51] 4 (0x4)
    [52] 0 (0x0)
    [53] 0 (0x0)
    [54] 0 (0x0)
    [55] 0 (0x0)
    [56] 0 (0x0)
    [57] 0 (0x0)
    [58] 4 (0x4)
    [59] 0 (0x0)
    [60] 0 (0x0)
    [61] 0 (0x0)
    [62] 0 (0x0)
    [63] 0 (0x0)
    [64] 0 (0x0)
    [65] 4 (0x4)
    [66] 0 (0x0)
    [67] 0 (0x0)
    [68] 0 (0x0)
    [69] 0 (0x0)
    [70] 0 (0x0)
    [71] 0 (0x0)
    [72] 4 (0x4)
    [73] 0 (0x0)
    [74] 0 (0x0)
    [75] 0 (0x0)
    [76] 0 (0x0)
    [77] 0 (0x0)
    [78] 0 (0x0)
    [79] 0 (0x0)
    [80] 0 (0x0)
    [81] 0 (0x0)
    [82] 0 (0x0)
    [83] 0 (0x0)
    [84] 0 (0x0)
    [85] 0 (0x0)
    [86] 0 (0x0)
    [87] 0 (0x0)
    [88] 0 (0x0)
    [89] 0 (0x0)
    [90] 0 (0x0)
    [91] 0 (0x0)
    [92] 0 (0x0)
    [93] 0 (0x0)
    [94] 0 (0x0)
    [95] 0 (0x0)
    [96] 0 (0x0)
    [97] 0 (0x0)
    [98] 0 (0x0)
    [99] 0 (0x0)
    [100] 0 (0x0)
    [101] 0 (0x0)
    [102] 2 (0x2)
    [103] 0 (0x0)
    [104] 0 (0x0)
    [105] 0 (0x0)
    [106] 0 (0x0)
    [107] 0 (0x0)
    [108] 0 (0x0)
    [109] 0 (0x0)
    [110] 0 (0x0)
    [111] 0 (0x0)
    [112] 0 (0x0)
    [113] 0 (0x0)
    [114] 0 (0x0)
    [115] 0 (0x0)
    [116] 0 (0x0)
    [117] 0 (0x0)
    [118] 0 (0x0)
    [119] 0 (0x0)
    [120] 0 (0x0)
    [121] 0 (0x0)
    [122] 0 (0x0)
    [123] 0 (0x0)
    [124] 0 (0x0)
    [125] 0 (0x0)
    [126] 0 (0x0)
    [127] 0 (0x0)

    Recording data PGA gain 59.5dB same settings

    Isn't the noise suppressor working?

    test404.wav

    test408.wav

    test410.wav

    test411.wav

    test412.wav

  • Best Regards,

  • Hi,

    The settings looks ok.

    So it's not breaking up but just noise, are these just different recordings of the same settings?

    Do you have a recording with gain lower than 50dB for comparison?

    Thanks.

  • Thanks again.

    test404.wav, test408.wav, test410.wav, test411.wav, test412.wav
    These settings are the same. AGCGAIN = 59.5dB
    The only difference is the input sound of the microphone.

    AGCGAIN = 40.0dB
    test401.wav, test405.wav

    AGCGAIN = 50.5dB
    test402.wav, test406.wav

  • I think this is just noise amplified, this ECM does not have good SNR and by increasing the gain the noise is just being amplified further.

    If you use a sinewave, I believe this is clean.

  • Thank you very mutch.