Search Results for: filter

Biquad calculator v3

Posted on September 2, 2021 by Nigel Redmon

The latest version of the biquad calculator. It also takes on the functionality of the frequency response grapher:

Posted in Biquads, Digital Audio, Filters, Widgets | Tagged | 54 Comments

AM widget

Posted on October 2, 2020 by Nigel Redmon
Posted in Amplitude Modulation, Widgets | Leave a comment

Further thoughts on wave table oscillators

Posted on January 4, 2020 by Nigel Redmon

I see regular questions about wave table oscillators in various forums. While the process is straight forward, I sympathize that it’s not so simple to figure out what’s important if you really want to understand how it works. For instance, … Continue reading →

Posted in Digital Audio, Oscillators, Wavetable Oscillators | 12 Comments

WaveUtils updated

Posted on April 30, 2019 by Nigel Redmon

WaveUtils needed only a minor change for compatibility with the WaveTableOsc update—addWaveTable changes to AddWaveTable. But I added something new while I was at it. The original wave table articles advocated minimizing the number of tables necessary—one per octave—by allowing … Continue reading →

Posted in Source Code, Wavetable Oscillators | 17 Comments

How I write code

Posted on April 26, 2019 by Nigel Redmon

Next article I’ll post an update of our wave table oscillator, but first I’ll take the opportunity to discuss how I write code these days. Maybe it will help make sense of some of the choices in the code I … Continue reading →

Posted in Source Code | 18 Comments

Floating point denormals

Posted on April 19, 2019 by Nigel Redmon

There’s another issue with floating point hardware that can easily cause serious performance problems in DSP code. Fortunately, it’s also easy to guard against if you understand the issue. I covered this topic a few years ago in A note … Continue reading →

Posted in Math | 10 Comments

Floating point caveats

Posted on April 19, 2019 by Nigel Redmon

The equivalent of “When I was your age, we use to walk to school in the snow. Barefoot”, in DSP, is to say we used to do DSP in fixed point math. The fixed-point system could be made of integer … Continue reading →

Posted in Math | 9 Comments

Sampling theory, the best explanation you’ve ever heard—End notes

Posted on September 21, 2018 by Nigel Redmon

A few words before moving on to other topics… We’ve looked at why digital sample represent ideal impulses, and why any point between samples represents a value of zero. And, as a result, audio samples don’t represent the audio itself, … Continue reading →

Posted in Digital Audio, Sampling Theory | Tagged | 2 Comments

Sampling theory, the best explanation you’ve ever heard—Part 3

Posted on August 25, 2017 by Nigel Redmon

We look at what Pulse Amplitude Modulation added to our analog source audio. What did PAM add? Earlier, we noted that the PAM signal represents the the source signal plus some additional high frequency content that we need to remove … Continue reading →

Posted in Digital Audio, Sampling Theory | Tagged | 5 Comments

Sampling theory, the best explanation you’ve ever heard—Part 1

Posted on August 16, 2017 by Nigel Redmon

I’ll start by giving away secrets first: Individual digital samples are impulses. Not bandlimited impulses, ideal ones. We know what lies between samples—virtual zero samples. Audio samples don’t represent the source audio. They represent a modulated version of the audio. … Continue reading →

Posted in Digital Audio, Sampling Theory | Tagged | 4 Comments