Notes on Digital Signal Processing: Practical Recipes for Design, Analysis and Implementation

Note 62. Generating Analytic Signals with Frequency-Shifted FIR Lowpass Filters

A useful technique for designing FIR analytic signal generation (ASG) filters is presented by Reilly et al. in [1]. The basic idea is to design a “standard” lowpass filter having real-valued coefficients, and then phase-shift the impulse response coefficients such that the filter’s passband is shifted to cover only positive frequencies and the stopband is shifted to cover only negative frequencies. The phase-shifted coefficients are complex-valued. The details are provided in Design Procedure 62.1.

Example 62.1 attempts to implement a broadband, or “almost-all-positive pass” ASG filter using the approach of Design Procedure 62.1. Example 62.2 implements a more pronouncedly ...