Most engineering concepts live in textbooks and MATLAB scripts — you read about a Fourier transform, a PID loop, or a constellation diagram, but you rarely get to touch one. I'm a game developer by day and an Electronics & Communication Engineer by training, and I kept thinking: why can't these be things you just open in a browser and play with?
So I built four of them. No installs, no accounts — click a link and start turning knobs. Each one is written from scratch in React + TypeScript with the actual math implemented by hand (no DSP or simulation libraries). Here's what I made and the interesting problem behind each.
▶ Live demo: https://dsp-signal-lab.vercel.app/ · Code: https://github.com/Dhananjay-ku-seth/dsp-signal-lab
A signal generator (sine / square / sawtooth / triangle) feeding a live 2048-point FFT spectrum analyzer, with injectable white noise and switchable digital filters (lowpass / highpass / bandpass / notch).
The fun part: the FFT is real, not a fake animation. It uses the Web Audio API's AnalyserNode, so when you pick a square wave you can watch the odd harmonics appear in the spectrum, then sweep a lowpass cutoff down and see them get attenuated in real time. Switch to microphone mode and whistle — the peak tracker finds your pitch.
