Digital Filters Part 2
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The document discusses different types of digital filters including Infinite Impulse Response (IIR) filters and multirate filters. IIR filters use feedback and have an infinite impulse response. They are potentially unstable but more efficient than FIR filters. IIR filters are usually designed to duplicate analog filter responses and implemented as cascaded second-order sections. Multirate filters involve changing the sample rate, such as decimation which decreases the sample rate, and interpolation which increases the sample rate. Adaptive filters can modify their transfer function based on an optimization algorithm to model non-stationary signals and are used for applications like echo cancellation.
Digital Filters Part 2
- 1. DIGITAL FILTERS Source: ANALOG DEVICES Part 2: Infinite Impulse Response (IIR) Filters
- 2. Introduction Purpose This module introduce the technology of Infinite Impulse Response (IIR) Filters, Multirate Filters and Adaptive Filters. Outline Introduce the technology of Infinite Impulse Response (IIR) Filters Introduce the technology of Multirate Filters. Introduce the technology of Adaptive Filters. Contents 23 pages Duration 15 Minutes
- 3. Bandpass and Bandstop Filters Designed from Lowpass And Highpass Filters
- 4. Infinite Impulse Response (IIR) Filters Uses Feedback (Recursion) Impulse Response has an Infinite Duration Potentially Unstable Non-Linear Phase More Efficient than FIR Filters No Computational Advantage when Decimating Output Usually Designed to Duplicate Analog Filter Response Usually Implemented as Cascaded Second-Order Sections (Biquads)
- 5. Hardware Implementation Of Second-order IIR Filter (Biquad) Direct Form 1
- 6. IIR Biquad Filter Direct Form 2
- 7. IIR Biquad Filter Simplified Notations
- 8. Review Of Popular Analog Filters Butterworth All Pole, No Ripples in Passband or Stopband Maximally Flat Response (Fastest Roll-off with No Ripple) Chebyshev (Type 1) All Pole, Ripple in Passband, No Ripple in Stopband Shorter Transition Region than Butterworth for Given Number of Poles Type 2 has Ripple in Stopband, No Ripple in Passband Elliptical (Cauer) Has Poles and Zeros, Ripple in Both Passband and Stopband Shorter Transition Region than Chebyshev for Given Number of Poles Degraded Phase Response Bessel (Thompson) All Pole, No Ripples in Passband or Stopband Optimized for Linear Phase and Pulse Response Longest Transition Region of All for Given Number of Poles
- 9. IIR Filter Design Techniques Impulse Invarient Transformation Method Start with H(s) for Analog Filter Take Inverse Laplace Transform to get Impulse Response Obtain z-Transform H(z) from Sampled Impulse Response z-Transform Yields Filter Coefficients Aliasing Effects Must be Considered Bilinear Transformation Method Another Method for Transforming H(s) into H(z) Performance Determined by the Analog System’s Differential Equation Aliasing Effects do not Occur Matched z-Transform Method Maps H(s) into H(z) for filters with both poles and zeros CAD Methods Fletcher-Powell Algorithm Implements Cascaded Biquad Sections
- 10. Throughput Considerations For IIR Filters Determine How Many Biquad Sections (N) are Required to Realize the Desired Frequency Response Multiply this by the number of instruction cycles per Biquad for the DSP and add overhead cycles (5N + 2 cycles for the ADSP-21xx series, for example). The Result (plus overhead) is the Minimum Allowable Sampling Period (1 / fs) for Real-Time Operation
- 11. Comparison Between FIR and IIR Filters
- 12. Decimation Of a Sampled Signal By a Factor of M
- 13. Decimation Combined With FIR Filtering
- 14. Interpolation by a Factor Of L
- 15. Effects of Interpolation on Frequency Spectrum
- 16. Typical Interpolation Implementation Efficient DSP algorithms take advantage of: Multiplications by zero Circular Buffers Zero-Overhead Looping
- 18. Adaptive Filter
- 19. Digital Transmission using Adaptive Equalization
- 20. Linear Predictive Coding (LPC) Model of Speech Production
- 21. LPC Speech Companding System
- 22. All Pole Lattice Filter
- 23. Estimation of Lattice Filter Coefficients in Transmitting DSP
- 24. Additional Resource For ordering the ADSP-21xx, please click the part list or Call our sales hotline For additional inquires contact our technical service hotline For more product information go to http://www.analog.com/en/embedded-processing-dsp/adsp-21xx/processors/index.html Newark Farnell