Channel Capacity

Bandwidth B — 4000 Hz Signal-to-noise ratio — 20.0 dB Attempted rate R — 20000 bit/s

Live readouts

Capacity C—

Attempted rate R—

Headroom / overshoot—

SNR—

SNR (linear)—

Max PAM levels √(1+SNR)—

Link status—

The Shannon-Hartley theorem, C = B·log₂(1+SNR), is the exact maximum error-free bit rate of a channel with bandwidth B and signal-to-noise ratio SNR. Below C, Shannon proved coding can make errors arbitrarily rare. Above C, no coding scheme — however clever — can communicate reliably. It is a hard ceiling, not a rule of thumb.