Category Archives: FFT

Evaluating filter frequency response

Posted on December 1, 2016 by Nigel Redmon

A question that pops up for many DSP-ers working with IIR and FIR filters, I think, is how to look at a filter’s frequency and phase response. For many, maybe they’ve calculated filter coefficients with something like the biquad calculator … Continue reading →

Posted in Biquads, FFT, Filters, FIR Filters, IIR Filters | 27 Comments

A gentle introduction to the FFT

Posted on August 31, 2002 by Nigel Redmon

Some terms: The Fast Fourier Transform is an algorithm optimization of the DFT—Discrete Fourier Transform. The “discrete” part just means that it’s an adaptation of the Fourier Transform, a continuous process for the analog world, to make it suitable for … Continue reading →

Posted in Digital Audio, FFT | 11 Comments

The Fourier series

Posted on November 14, 1996 by Nigel Redmon

(Java is no longer supported by many popular browsers, and can be difficult to enable others…) Experiment with harmonic (Fourier) synthesis with this Java applet! The sliders represent the levels of the first eight harmonics in the harmonic series. The second harmonic … Continue reading →

Posted in Digital Audio, FFT, Fourier, Widgets | 3 Comments