SBAA497B May   2021  – April 2022 PCM3120-Q1 , PCM5120-Q1 , PCM6120-Q1 , TLV320ADC3120 , TLV320ADC5120 , TLV320ADC6120

 

  1.   Trademarks
  2. 1Introduction
  3. 2Infinite Impulse Response Filters
    1. 2.1 Digital Biquad Filter
  4. 3TLV320ADCx120 and PCMx120-Q1 Digital Biquad Filters
    1. 3.1 Filter Design Using PurePath Console
      1. 3.1.1 Example Generating Programmable Biquad Coefficients Using PurePath Console
    2. 3.2 How to Generate N0, N1, N2, D1, and D2 Coefficients with a Digital Filter Design Package
    3. 3.3 Avoid Overflow Conditions
    4. 3.4 Digital Biquad Filter Allocation to Output Channel
    5. 3.5 Programmable Coefficient Registers for Digital Biquad Filters 1–6
    6. 3.6 Programmable Coefficient Registers for Digital Biquad Filters 7–12
  5. 4How to Program the Digital Biquad Filters on the TLV320ADCx120 and PCMx120-Q1
  6. 5Typical Audio Applications for Biquad Filtering
    1. 5.1 Parametric Equalizers
  7. 6Crossover Networks
  8. 7Voice Boost
  9. 8Bass Boost
  10. 9Removing 50 Hz–60 Hz Hum With Notch Filters
  11.   A Digital Filter Design Techniques
    1.     A.A Analog Filters
  12.   B Related Documentation
  13.   B Revision History

2.1 Digital Biquad Filter

A Digital Biquad Filter is a second-order IIR filter with two poles and two zeros. “Biquad” is an abbreviation of “biquadratic.” Thus, a Digital Biquad Filter is an IIR filter whose transfer function is the ratio of two quadratic functions given by Equation 2 and the corresponding direct form II block diagram shown in Figure 2-1. In this equation, the coefficients are normalized so that a0 = 1 through the division of all the coefficients by a0.

Equation 2. GUID-B959924A-F63A-4079-B429-E4852E8D0E6F-low.gif
GUID-153846BA-1738-4B3C-B04C-695893E0EA6D-low.pngFigure 2-1 Direct Form II Biquad Filter