pale line: the signal. dark line: what arrived.

very channel adds something you didn't send. Wires do it, radios do it, conversations do it. This part of the site is about pulling the thing you meant back out, with circuits, with math, and with ciphers, which are noise on purpose.

• the RC low-pass
• RLC, resonance and Q
• the integrator, and a bronze computer
• the Wien bridge oscillator
• Fourier, 1822
• Bayes, 1763
• secrecy: Enigma and the one-time pad
• base 60 and base 20