SBAA492A September   2021  – April 2022 PCM3120-Q1 , PCM5120-Q1 , PCM6120-Q1 , TLV320ADC3120 , TLV320ADC5120 , TLV320ADC6120

 

  1.   Trademarks
  2. 1Introduction
  3. 2Automatic Gain Control
    1. 2.1 High Pass Filter
    2. 2.2 AGC Parameters
  4. 3AGC Results
    1. 3.1 Normal AGC Mode
    2. 3.2 Enhanced AGC mode
  5. 4Examples
  6. 5Related Documentation
  7.   A Revision History

3 AGC Results

This section discusses the AGC results for Normal AGC mode and Enhanced AGC mode. Output level vs Input level and THDN vs. Input level plots are included for the following cases

  • Backward sweep (High input (0 dB for example, 2 VRms ) to low input (-130 dB for example, 0.64 uVRms ) )
  • Forward sweep (Low input (-130 dB for example, 0.64 uVRms) to High input (0 dB for example, 2 VRms))
  • AGC disabled

Different configuration values for these plots are

Recommended setting for Noise Threshold when using AGC at different sampling frequencies are -85 dB for 16 KHz to 48 KHz, -70 dB for 96 KHz, -65 dB for 192 KHz.

  • Target Level = -34 dB
  • Maximum Gain = 24 dB
  • Attack Hysteresis = 1 dB
  • Release Hysteresis = 3 dB
  • Noise Hysteresis = 4 dB