#signalprocessing

https://shafq.at/fixed-point-tutorial-2.html

If you've ever wrestled with fixed-point math, scaling, and rounding, this blog post is for you!

I go deeper into binary arithmetic, division tricks, rounding, and what it really takes to build fixed-point systems that work.

As always, I appreciate all of your feedback and corrections.

Engineer busy designing something with a slide rule. AI Generated Image.

#EmbeddedSystems #DSP #FixedPoint

**iotar** @iotar@mastodon.online · Mar 26

Mar 26

iotar @iotar@mastodon.online

This is pretty cool.
#oscilloscope #SignalProcessing #fx

https://www.youtube.com/watch?v=47jlny15IEc

YouTubePutting Audio Effects on TextBy AIHVHIA

**Pustam | पुस्तम | পুস্তম** @pustam_egr · Mar 23 *

Mar 23 *

Pustam | पुस्तम | পুস্তম @pustam_egr

The Fourier Transform is a mathematical operation that transforms a function of time (or space) into a function of frequency. It decomposes a complex signal into its constituent sinusoidal components, each with a specific frequency, amplitude, and phase. This is particularly useful in many fields, such as signal processing, physics, and engineering, because it allows for analysing the frequency characteristics of signals. The Fourier Transform provides a bridge between the time and frequency domains, enabling the analysis and manipulation of signals in more intuitive and computationally efficient ways. The result of applying a Fourier Transform is often represented as a spectrum, showing how much of each frequency is present in the original signal.

$\hat{f} (ξ) = \int_{- \infty}^{\infty} f (x) e^{- i 2 π ξ x} d x, \forall ξ \in R .$

Inverse Fourier Transform:
$f (x) = \int_{- \infty}^{\infty} \hat{f} (ξ) e^{i 2 π ξ x} d ξ, \forall x \in R .$

The equation allows us to listen to mp3s today. Digital Music Couldn’t Exist Without the Fourier Transform: http://bit.ly/22kbNfi

Gizmodo · May 30, 2016Digital Music Couldn't Exist Without the Fourier TransformThis is the Fourier Transform. You can thank it for providing the music you stream every day, squeezing down the images you see on the Internet into tiny

#Fourier #FourierTransform #Transform

**Dan Stowell** @danstowell@mastodon.social · Mar 21

Mar 21

Dan Stowell @danstowell@mastodon.social

Come and work with us! Be a Postdoctoral Fellow in AI for Ultrasonic Bioacoustic Monitoring! All the details: https://www.naturalis.nl/en/about-us/job-opportunities/postdoctoral-fellow-in-ai-for-ultrasonic-bioacoustic-monitoring #academicjobs #postdoc #PDRA #netherlands #biodiversity #AI #AI4good #signalprocessing

NaturalisPostdoctoral fellow in AI for Ultrasonic Bioacoustic MonitoringNaturalis is looking for a postdoc in AI for Ultrasonic Bioacoustic Monitoring!

**Ayan Shafqat** @ashafq@hachyderm.io · Mar 21 *

Mar 21 *

Wavelet-Based Spectrum Analyzer!

FFT has long been the go-to method for visualizing audio spectra, but what if there’s a faster and more efficient alternative? Enter the Haar Wavelet Transform: a technique that provides logarithmic frequency resolution while being even more computationally efficient than FFT-based analysis.

Stay tuned for a deep dive into how wavelets can be used for real-time spectral analysis—no FFTs required!

Some preview: https://gist.github.com/ashafq/99d468dc5e52c7bea23ad4824e21161f

GIF

#dsp #wavelets #audio

**Ayan Shafqat** @ashafq@hachyderm.io · Mar 18

Mar 18

https://gist.github.com/ashafq/eef8ef391fb58be85b325c259ce591e3

Forget the AI hype - FFT is the real unsung hero of computing...

The Fast Fourier Transform (FFT) is everywhere: multiplying large numbers, audio and video compression, high-frequency trading, weather prediction - you name it. It’s also the foundation of other key transforms: DCT for image compression, MDCT for audio compression, MFCC for machine learning, and more.

FFT is the most underrated algorithm of the 20th and 21st century — change my mind.

The first time I saw the Fourier Matrix and finally understood the Cooley-Tukey FFT, I was hooked. There’s something beautiful and elegant about its tree-like structure. Someday, I will probably write about what happens when you unravel FFT's recursion, and how it is related to the `rbit` instruction on ARM CPU. And sometimes, I just sit at my computer, and code away to make FFT run faster. It's relaxing...

Here’s one of my little achievement: A 4-point complex-to-complex FFT in just **11** AVX2 instructions. By itself, a 4-point FFT isn’t much, but as a kernel, it helps build higher-order FFTs with blazing efficiency.

Full demo implementation is on GitHub, which computes 256 point FFT under 1 micro-second on 12th gen Intel Processors.

$static inline __m256 avx2_fft_kerneld4(__m256 vec) { __m256 top, bot, sum, diff; const __m256 NEGATE_MASK = _mm256_set_ps(-0.0F, 0.0F, 0.0F, 0.0F, 0.0F, 0.0F, 0.0F, 0.0F); top = vec; bot = _mm256_permute2f128_ps(vec, vec, 1); sum = _mm256_add_ps(top, bot); diff = _mm256_sub_ps(top, bot); constexpr auto PMASK1 = _MM_SHUFFLE(2, 3, 1, 0); constexpr auto PMASK2 = (2 << 4) | 0; _.m256 z = _mm256_permute2f128_ps(sum ] _mm256_permute_ps(diff, PMASK1), PMASK2); z = _mm256_xor_ps(z, NEGATE_MASK); constexpr int PMASK3 = 0 | (2 << 2) | (1 << 4) | (3 << 6); z = _mm256_castpd_ps(_mm256_permutedx64_pd(_mm256_castps_pd(z), PMASK3)); top = z; bot = _mm256_permute2f128_ps(z, z, 1); sum = _mm256_add_ps(top, bot); diff = _mm256_sub_ps(top, bot); _.m256 y = _mm256_permute2f128_ps(sum, diff, PMASK2); return y; I$

#signalprocessing #programming #simd

**Ayan Shafqat** @ashafq@hachyderm.io · Mar 18

Mar 18

#engineering #software #optimization

Engineering is all about figuring out what is “good enough” to get the job done...

Back in the '90s, John Carmack and the team at ID Software faced a significant challenge. The computationally expensive inverse square root was holding back their goal of achieving playable frame rates in games. John Carmack’s ingenious contribution, the Fast Inverse Square Root (FISR), was an amazing achievement. While he might not have been the very first to explore this idea, his implementation was both innovative and influential. Also, I am not sure if Carmack was aware of any prior art of FISR. (Correct me if I am wrong)

Fast-forward a few decades, and I now find myself working in the field of Audio Signal Processing. When it comes to computing signal strength in decibels (20 log10(x)), the standard approach can be quite expensive computationally. Thus, the code below was my little achievement. Is it accurate? Of course not! But, it is close enough to about half a decibel. It even becomes more accurate the closer the signal goes towards zero.

When processing speech data from a microphone, the signal strength is much lower than -30 dB FS, where this function is typically 0.6% accurate to the real function. That means those expensive calls to logarithmic functions can be safely eliminated in many real-world applications.

I really admire these kinds of small innovations. They might not get a lot of media attention or the spotlight, but they can have a tangible impact: whether it’s enabling a smooth gameplay of Quake III Arena or extending battery life by reducing computational overhead.

$static inline float db20Fast(float x) { union { float f; int32_t i; } z = {.f = x}; return ((float)(z.i - 0x3f7893f5)) * 0x1.815182p-21F; }$

**Academic Europe** @AcademicEurope@mstdn.business · Mar 18

Mar 18

Academic Europe @AcademicEurope@mstdn.business

Job - Alert

PHD TITLE: LOCALISATION AND SITUATIONAL AWARENESS FOR HIGH RELIABILITY IN INTEGRATED SENSING

Deadline: 2025-04-10
Location: Austria, Linz

https://www.academiceurope.com/job/?id=7203

#hiring #PhD #Research

**Dan Stowell** @danstowell@mastodon.social · Mar 14

Mar 14

Dan Stowell @danstowell@mastodon.social

Does anyone know an audio hash or audio fingerprint library, that works also with ultrasonic high-bandwidth sound? (i.e. not just audible frequencies). We want to hash soundfiles (WAV, FLAC, etc) in a database system to match duplicates. #signalprocessing #audiophile #audioengineering

**LavX News** @lavxnews@mastodon.cloud · Mar 6

Mar 6

https://news.lavx.hu/article/unlocking-the-spectrum-retrogram-plutosdr-brings-ascii-art-to-signal-analysis

Unlocking the Spectrum: Retrogram-PlutoSDR Brings ASCII Art to Signal Analysis

The Retrogram-PlutoSDR project transforms your terminal into a powerful wideband spectrum analyzer, marrying retro aesthetics with modern functionality. By leveraging the ADALM PlutoSDR hardware, it o...

#dsp #cepstrum #signal_processing

**Neural** @neural@tldr.nettime.org · Feb 12 *

**lapnect** @lapnect · Jan 27 *

Jan 27 *

lapnect @lapnect

Cepstrum Analysis
https://community.sw.siemens.com/s/article/Cepstrum-Analysis

**LavX News** @lavxnews@mastodon.cloud · Jan 25

Jan 25

https://news.lavx.hu/article/exploring-deep-space-communication-the-intersection-of-amateur-radio-and-advanced-technology

Exploring Deep Space Communication: The Intersection of Amateur Radio and Advanced Technology

In a fascinating blend of amateur radio and cutting-edge technology, enthusiasts are pushing the boundaries of communication by reaching out to deep-space probes. This article delves into the technica...

**LavX News** @lavxnews@mastodon.cloud · Jan 17

Jan 17

https://news.lavx.hu/article/decoding-the-future-the-power-of-cdma-in-modern-communications

Decoding the Future: The Power of CDMA in Modern Communications

As the demand for simultaneous device communication surges, Code Division Multiple Access (CDMA) emerges as a pivotal technology in mobile networks, satellite communications, and beyond. This article ...

**LavX News** @lavxnews@mastodon.cloud · Jan 11

Jan 11

https://news.lavx.hu/article/ingrid-daubechies-the-mathematician-behind-modern-imaging-honored-with-national-medal-of-science

Ingrid Daubechies: The Mathematician Behind Modern Imaging Honored with National Medal of Science

In a groundbreaking recognition, mathematician Ingrid Daubechies has been awarded the National Medal of Science for her transformative contributions to signal processing. Known as 'The Godmother of th...