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Noise observed in MIC Input capture in TLV320ADC3101 codec?

Other Parts Discussed in Thread: TLV320ADC3101

Hi,

I have configured the codec (tlv320adc3101) from linux user space.
I am able to capture the Audio using MIC input.
But some noises are recorded along with sound data. I have tried the capture with various sample rate frequencies like 8000, 16000, 48000, 96000 Hz.
8000 Hz sample rate frequency has more noise, 16000 Hz has less noise compared to 8000 Hz, where 48000 and 96000 Hz contains very less noise compared to lower frequency rates.
When sample rate increases, we are getting less noise.

I have attached the recorded wav files below for your reference.

1. 16000 Hz wav file

2. 48000 Hz wav file

3. 96000 Hz wav file

If you want i can share the codec configuration details.


Do you have any idea about this issue?

Regards,
Rajesh

  • Hi Rajesh,

    Could you share what kind of board you are using? Is it a custom board because there are various possible hardware related reasons causing noise in the audio record. I can mention some of the reasons - noise from power supply or noise from microphone, lines or connectors.
    Therefore I suggest to use an oscilloscope to observe the analog lines between microphone and codec to search for that noises.

    BR
    Tsvetolin Shulev
  • Hi Tsvetolin Shulev,

    We are using Renesas rcar H3 processor. It is a custom board. We will probe the analog lines and update the status.

    please find the codec configuration details below for your information,

    PAGE 0:

    0 1 2 3 4 5 6 7 8 9 a b c d e f
    00: 00 00 20 00 00 91 08 01 08 00 00 00 00 00 00 00
    10: 00 00 81 82 80 80 04 00 00 00 81 00 00 02 01 00
    20: 00 10 00 00 44 00 02 00 00 00 00 08 00 00 00 00
    30: 00 00 00 00 00 12 02 02 00 00 00 44 00 01 00 00
    40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    50: 00 c0 00 18 18 00 00 00 7f 00 00 00 00 00 00 00
    60: 7f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

    PAGE 1:

    0 1 2 3 4 5 6 7 8 9 a b c d e f
    00: 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    30: 00 00 00 00 3f 00 33 3f 00 33 00 00 00 00 03 00
    40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

    Regards,
    Rajesh
  • Hi Tsvetolin Shulev,

    We have checked the power supply and MIC lines, there is no noise in this section.

    One more update, For 48000 Hz we are configuring following PLL divider values,
    P - 1, R - 1, J.D(K) - 32, NADC- 8, MADC - 2, AOSL - 128, PLL_CLK_IN - 3072000 Hz.
    with above divider values, we are able to record without any noise.

    For 16000 Hz below are the PLL divider configuration values,
    P - 1, R - 1, J.D(K) - 32, NADC- 8, MADC - 2, AOSL - 128, PLL_CLK_IN - 1024000 Hz.
    with above divider values, background noise is coming along with sound data.

    Are the PLL divider values for 16 Khz is correct? If not please suggest the correct one.

    Thanks,
    Rajesh
  • Hi

    We are able to get the correct ADC_FS for 16000 Hz with below settings.
    P - 1, R - 3, J.D(K) - 32, NADC- 8, MADC - 6, AOSL - 128, PLL_CLK_IN - 1024000 Hz

    we have verified the 16KHz sample rate using CLKOUT pin by probing.

    But Still some background noise is there in 16KHz sample rate along with recorded data.

    Thanks,
    Rajesh