SBAA378B November   2019  – December 2023 PCM3140-Q1 , PCM5140-Q1 , PCM6140-Q1 , TLV320ADC3140 , TLV320ADC5140 , TLV320ADC6140

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 Infinite Impulse Response Filters
    1. 2.1 Digital Biquad Filter
  6. 3  TLV320ADCx140/PCMx140-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 FiIter 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
  7. 4 How to Program the Digital Biquad Filters on TLV320ADCx140/PCMx140-Q1
  8. 5 Typical Audio Applications for Biquad Filtering
    1. 5.1 Parametric Equalizers
  9. 6 Crossover Networks
  10. 7 Voice Boost
  11. 8 Bass Boost
  12. 9 Removing 50 Hz–60 Hz Hum With Notch Filters
  13. 10Revision History
  14. 11Digital Filter Design Techniques
    1. 11.1 Analog Filters

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-7D89DECF-295D-489B-A4E2-BF29BD1E4E74-low.gif
GUID-C19511F1-983C-46FD-AE8B-B0451F19E063-low.pngFigure 2-1 Direct Form II Biquad Filter